I'm a bit rusty with AE but I may need to use it over the weekend, I just need to pick some brains to answer this problem..

If an editor sends me an AE project file and all assets which he has created in Windows, will I be able to open and edit the project on my Mac?

All assets are JPGs, no video or sound.

Thanks for your help

Shouldn't be a problem, unless you have an old version and the editor has a newer one.