Member uploaded images I'm considering using Craft for a new site. One requirement will be allowing members to upload and manage images. With Craft, can I set a size requirement for member uploaded images? So for example, if I only wanted to allow 400x400 image size to be uploaded, could I lock it down so that any image smaller or larger will just give an error?

If that's not possible, is there a way to resize/crop a large image down to the correct size?
You can ad {author.username} to the file upload field, that way their files will always be in the folder of the user. 

With assets you can define scale sizes which works way better then forcing a fixed size. It doesn't stop someone from uploading a 36 Mp image though. As far as I know it's impossible to check the canvas size before upload.