Hiding these images is extremely simple and can be done for free with my favorite freeware browser - Y-Browser

First open Y-browser and select [options] -> [search files]. Now in the “Filename” field, input a picture title followed by “.*” as pictured below (since you don’t know what format the picture is). Then select [Options] -> [Start search]. You do not need to do this if you know the directory where the images are stored of course.

Once you have found your file in the list of search results, highlight it and select [Options] -> [File] -> [Attributes].

Now simply change “System” and “Hidden” to yes and select [Save].

repeat same for all files you want to be hide.

and finally restart the phone.