The way to get the Gallery and the Music apps to ignore folders on your phone is to create an empty file in the folder called ".nomedia
".
The easiest way to create that file is to plug your phone into a PC, explore the phone until you can find the folder that has your unwanted icons in it.
Then if you open Windows Notepad, click File -> Save As, navigate your way to the folder on the phone and then make sure that Notepad's Save As Type box says All Files (*.*) and does not say "Text Documents (*.txt)" you can now type .nomedia
(note the full stop/period at the start of the file name) and click Save.
If you've done it right the file should not have a Notepad icon in in Explorer, it should just have a default plain white, rectangular icon. Now safely remove the drive, unplug your phone and (after your phone's done a media scan) the icons should disappear from the gallery.