Can you please not put up duplicates in the galleries. If you want to reorganize the images into seasons I recommend you do it in source mode and move the pictures. Or better yet do it in a sandbox before you publish it onto the main page.
I'm sorry. I know you're trying to help improve the layout by sectioning the images by season and I appreciate that, but you're forgetting to remove certain images from certain sections, leaving others like myself to fix the problem.
I recommend you take this plan of yours where I've said and don't publish it onto the main gallery until you think your done. In a sandbox you can do whatever you want and make edits without any interference. Work smarter not harder.
I've never watched Avengers Assemble so I don't know which images go where but you do.
Making a sandbox is very easy. It's like making a separate gallery for a page. For a start you want to type this link into your personal profile (User:YK WONG 99/Sandbox), click on it and then click on "Create Article" and then put in whatever you want. You can copy and paste the entire Captain America gallery into it or just the Avengers Assemble section.
Would you prefer it if I set it up for you or would you rather try to do it yourself?
It's all done and ready for you, I'm sure you can figure out the rest. I just do you normally do and then you can publish your changes on the actual gallery later. Even when your done you can reuse for other purposes.