It isn't clear why your images can't be found. Spine uses the images folder path + attachment name to find each image file. If the attachment has a path set,it uses the path instead of the name. Please show how you have this setup in Spine so we can help you better.

If you want to go down the renaming route, you can use Find and Replace by limiting the scope to the path, then changing the path to the new version you need:
Tree view - Spine User Guide: Find and replace

If your use case happens to have no folders before the path that you may use in the Find field, you can check First occurrence and Regular expression
then type in the Find field: (.*) and in the Replace field: newfolder/$1 where instead of "newfolder" you can type the new path to use.