Problem with manually adding boxart images

[Bensalot]

Ok, I have been working with my pie for a while now and have had to self teach myself a lot of things. I would say I am relatively decent at it now but for the life of me I cannot figure out this problem. So I know you can use the default scraper and Sselphs scraper but I want to simply add images myself. I know how to link a rom to the image I want and it will show the image in the games list but the problem is I cannot figure out how to get these manually added images to show up when starting a rom. I found a workaround by scraping a rom and then renaming the new image the same thing as the one provided by the scraper. However, the last couple of days the scrapers have not been giving me any images at all. Basically if I add an image myself and link it to a rom, it will show up in the game list. Then when I load the rom, instead of showing the enlarged image, I simply get a black screen. Is there a way to fix this that I am missing? Any help would be appreciated.