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Images displayed on the web (including Moodle) should have as small a file size as possible, while still maintaining adequate quality. 

Many students these days access Moodle on their mobile devices and in some cases they will be paying for every mega byte of data they download.

Keeping image file sizes small means pages will load more quickly and it will consume less data. 

In order to do this a *few rules* can be followed:

# Images should typically be no more than a *few hundred KB*. If your image is larger than this it should be resized and/or compressed.
# Resize the picture *before* you upload it - making it smaller once it's uploaded will mean the file size will be larger than necessary.
A typical size for websites would be 450x300 pixels for a medium sized image.
# Save photographs as JPEG (you can choose to save at a lower quality to reduce filer size)
# Save illustrations and drawings as GIF or PNG.
# If you want to allow students to see a photo in high quality consider adding a thumbnail that links to the full-size, high quality image, so they can choose to download it when appropriate.

h4. *Compressing images using Microsoft Picture Manager* (Windows with Office installed):

# Locate the image you want to compress in Windows Explorer.
# Right click the image > *Open with...* > *Microsoft Office 2010*
# Click *Edit Pictures...* (from the middle of the top menu bar)
# Click *Compress Pictures* (from the bottom of the right-hand column)
# Choose Web pages (from the list on the right-hand column)
# Click *OK*.
# Your picture will be resized to 448X336 pixels and saved in a compressed format.

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h4. *Compressing images using Mac Preview* (Mac only):

# Open your image in preview.
# Click *Tools* (in top menu bar) > *Adjust Size...*
# Choose *pixels* from the width / height and enter 450 (or whichever size you are aiming for) in the width field. The height will adjust accordingly.
# Click *OK*.
# Click *View* (in the top menu bar) > *Actual Size* to see the real size of your image.
# Click *File* > *Save as...* and save your compressed file with a new name - so you keep your high quality large image.

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Instructions with images can be downloaded here: [http://alums.vassar.edu/images/volunteer/image-reductions-in-preview.pdf|http://alums.vassar.edu/images/volunteer/image-reductions-in-preview.pdf]