Reduce the size of pictures and attachments

Reduce the size of pictures and attachments

When you send a message that exceeds the message size limit for either your or the recipient's mail server, the message will be returned to you and not delivered. This is often called a "bounced" message. Optimizing the size of pictures and attachments for e-mail helps to avoid exceeding the maximum message size limits associated with most e-mail accounts.

In addition to a per-message size limit, many e-mail accounts include a mailbox or account storage limit. Large attachments can not only fill a recipient's mailbox but increase your own Outlook data file size and mailbox. By default, a copy of each message that you send is saved to the Sent Items folder in Outlook.

What would you like to do?

There are two ways to reduce the size of pictures that you attach to e-mail messages in Outlook:

  1. Reduce the picture dimensions    Mobile phones and digital cameras can create very large images. Compressing the image to a smaller width and height can greatly reduce the file size. This option is available for pictures that are attached, but not displayed within the message body.

  2. Compress the picture resolution    By decreasing the dots per inch (DPI), file size is reduced, but the quality of the image is also impacted. Displaying images on a computer monitor requires a lower DPI than images that are printed. If the recipient doesn’t need higher quality resolutions, use a lower setting. This option is available for pictures that appear within the message body.

In all cases, the original picture file saved on your computer hard disk or memory device is not modified. Only the copy of the picture being sent is reduced in size.

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When you add attachments in Outlook, you can reduce picture attachments on a per-message basis. When you choose to resize large images, any attached image is reduced to a maximum resolution of 1024x768 pixels.

Note:  If you embed the picture in the message body — the picture appears in the message — by using the Picture command in the Illustrations group, the image attachment resize feature is not available.

  1. Create a new e-mail message in Outlook.

  2. On the Insert tab, in the Include group, click Attach File and select the picture file you want to attach.

    Tip:  You can also drag and drop a picture from Windows Explorer. The picture file will be attached to the e-mail message.

  3. In the message window, click the File tab.

  4. Under Image Attachments, click Resize large images when I send this message.

    Picture attachment resize options in the Backstage view

  5. Click the Message tab to return to your message.

  6. When you are finished composing your e-mail message, click Send.

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When you use Windows Explorer to select picture files and then create an e-mail message, you have multiple resize choices.

  1. Open Windows Explorer by clicking Start, and then double-clicking Computer.

    Keyboard shortcut    To open Windows Explorer, press Windows logo key+E.

  2. Navigate to the folder that contains the pictures you want to send.

  3. Select a picture. To select multiple files, press and hold CTRL as you click each file.

  4. Right-click a selected file, point to Send To, and then click Mail Recipient.

    The Attach Files dialog box appears.

  5. In the Picture size list, click the image size that you want.

    Resize picture attachment options

    An estimate of the new file size appears.

    A new Outlook message window appears with the attached picture.

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Note:  This option is available only for pictures that appear in the body of a message.

When you do not need every single pixel in an image to get an acceptable version of it for your target destination, you can reduce or change the resolution. Reducing or changing the resolution can be effective with images that you have scaled to be smaller, because their dots per inch (dpi) actually increase in that case. Changing the resolution can affect image quality.

  1. Click the picture or pictures that you want to change the resolution for.

  2. Under Picture Tools, on the Format tab, in the Adjust group, click Compress Pictures.

    Adjust group on the ribbon

    If you do not see the Picture Tools and Format tabs, make sure that you selected a picture. You may have to double-click the picture to select it and open the Format tab.

  3. To change the resolution for the selected pictures only and not all of the pictures in the document, select the Apply only to this picture check box.

  4. Under Target output, click the resolution that you want.

Important:  Compressing a picture to reduce the size of the file changes the amount of detail retained in the source picture. This means that after compression, the picture can look different than before it was compressed. Because of this, you should compress the picture before applying an artistic effect.

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The amount of reduction possible depends on the type of file format and content. For example, a Notepad .txt file will compress considerably. A Microsoft Word document in the .docx file format is already compressed; further compression will have little impact on the file size.

Note:  For more information specific to reducing picture files, see the section Reduce the size of picture attachments..

  1. Open Windows Explorer by clicking Start, and then double-clicking Computer.

    Note:  Double-click My Computer in Windows XP.

    Keyboard shortcut    To open Windows Explorer, press Windows logo key+E.

  2. Navigate to the folder that contains the file you want to send.

  3. Select a file. To select multiple files, press and hold CTRL as you click each file.

  4. Right-click the selection, point to Send To, and then click Compressed (zipped) Folder.

  5. Select the newly created compressed file.

    The file name will match the original file's name but will have a different icon. If you have configured Windows to display file extensions, the file name will end with an extension of .zip.

  6. Point to Send To, and then click Mail Recipient.

    A new Outlook message window appears.

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The following is a list of best practices to use when sending pictures and attachments:

  • Post or publish large attachments    - If you're sending attachments or pictures to someone with whom you are willing to share a stored location in the cloud, or on your organization's network, you can include a link to that location in your e-mail message.

  • Limit the size of your your attachments    - This is a general guideline; for slower, connections (such as a mobile device) you should use a much smaller size, such as 250 kilobytes (KB). If you must send larger attachments, verify the maximum size of the message that you can send. Your mail server administrator or the organization providing your email service can tell you this. Likewise, ask the recipient what their maximum limit is. Finally, consider the recipient's Internet connection speed. Downloading a large attachment on a mobile internet connection can take a long time.

  • Send multiple attachments by using several e-mail messages    - Multiple smaller messages have a higher likelihood of being delivered versus one large message. This technique might help you avoid per-message limits, but the recipient's mailbox limit can still be exceeded. Any messages received after a person's mailbox has reached its storage limit can sometimes be rejected.

  • Use compressed graphic file formats    - There are far too many graphic file formats to list here, but of the most commonly used, the best picture file formats for e-mail are .jpg, .png, and .gif. The largest graphics file formats are those that are not saved in a compressed file format, such as .tif and .bmp (the default file format of Windows Paint).

  • Use smaller original files    - The size of a photo taken by a mobile phone or a digital camera is typically large, even when saved in a compressed file format such as .jpg. It's not uncommon for a single picture to be several megabytes. Remember that the size of the e-mail message will increase by approximately one-third while in transit on the internet. Use a lower resolution setting on your camera when taking a digital photo. Use compressed file formats such as .jpg. In a graphics program, crop photographs to the essential content.

  • Use a file compression utility    - In addition to third-party utilities, Windows includes a file compress utility that uses the compressed .zip file format. Many attachment file formats can be reduced with the use of a compression utility. The amount of reduction will be minimal with some file formats that are already saved in a compressed format. For example, a Notepad .txt text file will reduce dramatically, while a .jpg image will not. The .jpg file format is already a compressed file format.

  • Review your Sent Items folder    - By default, a copy of each message that you send is kept in the Sent Items folder. This increases the size of your Outlook Data File (.pst), which can, with certain accounts, count against your mailbox size limit because the sent items are saved on your mail server.

Important:  Compressing a picture to reduce the size of the file changes the amount of detail retained in the source picture. This means that after compression, the picture can look different than before it was compressed. Because of this, you should compress the picture before applying an artistic effect.

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What would you like to do?

There are two ways to select pictures to automatically reduce them in size and include them as an attachment to an e-mail message — in Microsoft Office Outlook, or from Windows Explorer.

Note: Your original picture will not be modified. Only the copy of the picture being sent will be reduced in size.

  1. Create a new e-mail message in Outlook.

  2. On the Insert tab, in the Include group, click Attach File.

    Tip: You can also drag and drop a picture from Windows Explorer. The picture file will be attached to the e-mail message.

  3. On the Insert tab, click the Include Dialog Box Launcher Button image .

  4. In the Attachment Options pane, under Picture options, in the Select picture size drop-down list, click the size of the picture you want to include.

    Attachment Options pane

    Note: If you embed the picture in the body of the message by using the Picture command in the Illustrations group, the automatic picture resize feature is not available.

  5. When you are finished composing your e-mail message, click Send.

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  1. Open Windows Explorer by clicking Start, and then double-clicking Computer.

    Keyboard shortcut  To open Windows Explorer, press Windows logo key+E.

  2. Navigate to the folder that contains the pictures you want to send.

  3. Select a picture. To select multiple files, press and hold CTRL as you click each file.

  4. Right-click a selected file, point to Send To, and then click Mail Recipient.

    The Send Pictures via E-mail dialog box appears.

  5. Click Make all my pictures smaller, and then click OK.

    Send Pictures bia E-mail dialog box

    Note: To specify the exact size to make the picture, click Show more options, and then click the size you want.

    A new Outlook message window appears with the attached picture.

  6. Enter the recipient information in the To, Cc, and Bcc boxes.

  7. If you want, change the subject information in the Subject box.

  8. If you want, change or enter any information you want to include in the message body.

  9. Click Send.

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The following is a list of best practices to use when sending pictures and attachments:

  • Post or publish large attachments    - If you're sending attachments or pictures to someone with whom you are willing to share a stored location in the cloud, or on your organization's network, you can include a link to that location in your e-mail message.

  • Limit the size of your your attachments    - This is a general guideline; for slower, connections (such as a mobile device) you should use a much smaller size, such as 250 kilobytes (KB). If you must send larger attachments, verify the maximum size of the message that you can send. Your mail server administrator or the organization providing your email service can tell you this. Likewise, ask the recipient what their maximum limit is. Finally, consider the recipient's Internet connection speed. Downloading a large attachment on a mobile internet connection can take a long time.

  • Send multiple attachments by using several e-mail messages    - Multiple smaller messages have a higher likelihood of being delivered versus one large message. This technique might help you avoid per-message limits, but the recipient's mailbox limit can still be exceeded. Any messages received after a person's mailbox has reached its storage limit can sometimes be rejected.

  • Use compressed graphic file formats    - There are far too many graphic file formats to list here, but of the most commonly used, the best picture file formats for e-mail are .jpg, .png, and .gif. The largest graphics file formats are those that are not saved in a compressed file format, such as .tif and .bmp (the default file format of Windows Paint).

  • Use smaller original files    - The size of a photo taken by a mobile phone or a digital camera is typically large, even when saved in a compressed file format such as .jpg. It's not uncommon for a single picture to be several megabytes. Remember that the size of the e-mail message will increase by approximately one-third while in transit on the internet. Use a lower resolution setting on your camera when taking a digital photo. Use compressed file formats such as .jpg. In a graphics program, crop photographs to the essential content.

  • Use a file compression utility    - In addition to third-party utilities, Windows includes a file compress utility that uses the compressed .zip file format. Many attachment file formats can be reduced with the use of a compression utility. The amount of reduction will be minimal with some file formats that are already saved in a compressed format. For example, a Notepad .txt text file will reduce dramatically, while a .jpg image will not. The .jpg file format is already a compressed file format.

  • Review your Sent Items folder    - By default, a copy of each message that you send is kept in the Sent Items folder. This increases the size of your Outlook Data File (.pst), which can, with certain accounts, count against your mailbox size limit because the sent items are saved on your mail server.

Important:  Compressing a picture to reduce the size of the file changes the amount of detail retained in the source picture. This means that after compression, the picture can look different than before it was compressed. Because of this, you should compress the picture before applying an artistic effect.

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