Instructions for preparing images for this website using photoshop:
Open Adobe Photoshop.
Open the image you wish to upload in photoshop using "file>open"
Select "image>image size"
Set resolution to 72 px per inch
Set your Image size (a maximum width of 500px is good for this website or 85px if you are creating a user image)
Click "OK"
Select "file>save for web"
Under the settings dropdown select JPEG medium
Make sure the image is as small as possible by adusting the quality setting (without loosing image quality), your images should be a maximum of around 40K. You can view the images size at the bottom left of the window
Click "OK" to save your newly compressed image in a different location to the original image.