Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics

I was gonna make the collision system in my game work by detecting the tile graphics themselves and their positions. (for example, a dude moves if there is 8 pixels of space next to him, and can't move any further if there is a brick tile right next to him without any space inbetween)

I would need to see some code example to know how to make it.

If you have MPAGD then take a look at EngineZX.asm then search (if memory serves) for "cang" as those routines check if a 16x16 sprite can move in the 4 directions.  It's all commented.