@sleepybisexual From a bit of searching around it seems that Anbernic might typically be using fake-08 as the emulator, in which case (https://github.com/jtothebell/fake-08):

".p8 text file carts and .p8.png image file carts are supported."

So it may be enough to just rename it to .p8.png?

(I would check on my own Anbernic handheld but I believe that different models sometimes use different firmware with different emulators, so without knowing your exact model I can't know whether the answer is the same)