I noticed that a lot a people including me have had a hard time ripping sprites from Genesis mainly because of the annoying black backgrounds that most Genesis games have are shared with the back onlines of a lot of characters and objects, well this emulator I found online fixes that issue by having a special color key under debug that allows the background to be turned to bright pink, thus much easier sprite ripping. Download link-
http://www.mediafire.com/?6uz01cghqa67hn1
Note: I didn't make this emulator I just reuploaded it on mediafire because its is very hard to find a working link for this online.