Have you tried simply loading each card in singularly? Or placing them in a single line per set and using partial drawing? On mobile atm and sick as a nutter, but can followup later to draw a graphic with code to explain what is what, can you share a link to said images? Doesn’t have to be full resolution, you can blur them if needs be but keep the dimension and content in place so I can get err a clearer idea of what these large images are.
Although C# is also my choice language, it pays to study several others, their basics, but avoiding their usage is still wholly optional, at least learn Visual Basic, it’s a fun scripting language and you can find my guide on its usage in my profile.