For imgur, consider using jpg/jpeg rather than png. Even though on your end, your png may be 48kb, imgur may rescan it as a larger file.
As a jpg/jpeg, and in my experience, it stays true to the size of what I upload to their site.
Adobe's reference:
"JPEG vs. PNG.
At some point in your life, you may be faced with the all-important decision of whether to store your digital images as JPEGs or PNGs.
JPGs/JPEGs go through a compression process to significantly reduce the image file size — making them easier to store and load on webpages.
PNGs take up more storage space than JPGs/JPEGs. One thing PNGs offer that JPEGs don’t is the ability to handle graphics with transparent backgrounds."