This happens when image is bigger than the program window. If the window is resized enough to fit in the image entirely without needing to shrink it, the quality is retained.
Steps to reproduce -
- Open any image in Coreavor
- Resize the window smaller than image so that the image will also be auto-resized
Example -

As you see the text is blurred.
This Stack Overflow question looks similar.
This happens when image is bigger than the program window. If the window is resized enough to fit in the image entirely without needing to shrink it, the quality is retained.
Steps to reproduce -
Example -

As you see the text is blurred.
This Stack Overflow question looks similar.