Textures causing processing problems?

I have had a problem on my android game where it has been overheating and I now believe the reason for this is because of the textures / images in my game. At first I thought it could of been the file type but now I understand this doesn’t matter as unity converts the file types anyway so now I think there must be some settings that need changing somewhere. Anyone know what I need to do?

EDIT: I have compressed all texture files and now my phone still overheats when playing but it takes a lot longer

Just might be worth checking its not your phone?