Reading Arithmetic Coded JPEG Files Is Not Implemented

While writing the previous post, I found myself being lazy and wanted to dig up an image to use instead of taking a screenshot of the error message myself. Finding one, I proceed to download it for editing in photoshop, however I was unprepared for the error I was about to find.

“Could not complete your request because reading arithmetic coded JPEG files is not implemented.”

What!? A quick Google search yields a possible answer. Perhaps the image file I had was using an incorrect extension for its actual type! The forum post lists gif, so I change my extension to gif. Nope. Okay, time for the good old fashioned hex editor. I open up the file in Notepad++ and look at the header information. What was that? Right there at the top? PNG! I have found the problem.  A quick extension change later and I was on my way to throwing the file into Photoshop.

Note on the featured image: I took an existing image and typed some gibberish into the hex code which corrupted the image. Instant artifacts!

Source for solution https://forums.adobe.com/thread/362691?tstart=0