Pixelations of Images when image gets smaller

If this template helps then use it. If not then just delete and start from scratch.

OS (e.g. Win10):
PsychoPy version (e.g. 3.1.0):
Standard Standalone? (y/n) Yes
What are you trying to achieve?:
I am trying to develop a visual acuity chart ( The chat mostly read at the eye clinics) with pictures. I have been able to make the program run and collect some reposes, however as because the images are of different sizes in degrees units, when the image becomes very small (for instatnce at 0.50 degrees) then its gets pixelated with is not ideal for the construction of the chart. I am working with .png images though (which are of very good quality ). How do I get rid of the pixelations?
What did you try to make it work?:
I need some suggestions to work with
What specifically went wrong when you tried that?:
Include pasted full error message if possible. “That didn’t work” is not enough information.