In theory yes, but not really. On the surface all you need is an image editor that can save in 8bit .png format with user defined palette and an editor that will output .txt files. I've never seen an image editor that would work, but I'm sure they're out there. Problem is, there's no way to pack the data on a phone, and phones require packed modules to play. IOW, the character you create would only run on a PC. Assuming you can get any sort of editing environment set up at all, it's going to be a very clunky, slow, and buggy ordeal. And like I said before, whatever you make won't be usable until you move it to a PC anyway. Phones are fantastic media consumption devices, but they very much suck at creation.
DC