I'm looking into expressionEngine as a CMS for a project i'm working on. I'm not sure if EE works with Custom PHP/JQuery. I'm want to allows users to upload images, Each user's images would go into the user's folder named after his userid. User can then access his uploaded images y clicking on show all images... Something along this liken. I have this done in Pure PHP, but the questions is can this be done in EE and how efficient or easy it is to do so.
I don't see why you couldn't accomplish these things within EE. EE has some good image gallery setups, and custom programming (as of EE 2.0) relies on CodeIgniter.
http://www.packtpub.com/article/expressionengine-creating-a-photo-gallery
Be willing to learn the "EE" (now "CodeIgniter") way of doing it. But sure, you could easily build your own system on top of EE.
A bonus is that the EE community is very friendly and active. Plus there are some great developers, such as Leevi Graham:
And some more specific examples:
http://codeigniter.com/user_guide/libraries/file_uploading.html
http://jefim.eu/blog/2009/10/image-file-upload-with-codeigniter/
http://codeigniter.com/forums/viewthread/80610/
Some more good information:
http://net.tutsplus.com/articles/web-roundups/30-awesome-codeigniter-tutorials-for-all-skill-levels/