Output does not match user specified input

I download an art file (PNG) which designed 9.3"x 8.2" (2790x2460px) input and after upscaled it , I tried to save both format 1) preserve source format and 2) PNG format. Saved file doesn’t match user specified input and keep changing it as (2791x2461 px) I use Art&CG model. If anyone else experienced the same issue and figured out how to adjust setting to get correct output please help me out.