OK so big update on the "failed to load character_image.png" glitch.
So first, it would have appeared that I was half right and half wrong, in the sense that yes the glitch seems to be connected to the save files but it isn't related directly to the save count.
It would seems that only certain saving spots (Save spot 2 and 9) are subjected to the glicth.
I discovered that after trying to "fix" a glitch save file were I had barely saved (less than 30 saves). I duplicated the save file on the first save spot and loaded the game from the save spot 1 (mind you it was still the same data, I just changed the placement of the file and deleted the old one) and the glitch just disappeared.
I still can't quite figure out why the glitch occur but at least I found a way to avoid it. (If you were to play on one of the save spot mentioned please tell me if the glitch occured and if duplicating the save file in another spot fixed the problem. If you're playing on a different save spot and the glitch still occured, could you report it here and detail the save spot and save count)