Hi, I made a program with the requirements you described, namely:
1) save the screenshots to the list when you click PrtSc
2) pasting screenshots from the list to the clipboard
3) inserting a screenshot when clicking (Ctrl + v) from the clipboard, and delitting it from the list
4) gallery:
-viewing screenshots,
-the ability to remove unnecessary,
-the ability to download all the pictures from the folder to the list for further insertion
5) a pop-up message in the corner of the screen showing the total number of screenshots in the list, or warning that there are no screenshots left in the list
6) cross-platform program
I am ready to demonstrate. Have a nice day.