EXPORT FRAME does not export the exact identical frame... the exported frame gets compressed!

I don't know why, but after upgrading to the newest Premiere Pro, now whenever I use the "export frame" button to export a frame, the exported frame looks faded and pale, like it has less contrast. I tried exporting the exported frame a couple times, and it got grainier and grainier. Premiere Pro is compressing the file each time, so the quality gets lower and lower. Why is it doing this?

Where is the settings menu for the exported frame so I can bump the image quality back up? 

This is just frustrating...

I don't understand why Adobe did this. I'm baffled.