Report JPG linear/progressive save method

A script add-in could work out the information and display it in a column or Info Tips, but would be fairly complicated to write (since it'd have to parse the JPEG headers, although some people suggest just looking for a particular pair of bytes in the file, which I don't think would be reliable).

But if you want a way to quickly list all progressive JPEGs below the current folder, and don't mind it being in a command prompt, you could make an Opus button which uses ExifTool to print a list of them:

Function: MS-DOS Batch Function

cd {sourcepath}
"C:\Path\To\ExifTool\ExifTool.exe" -r -p "$filepath" -if "$EncodingProcess =~ /Progressive/ or $Photoshopformat =~ /Progressive/" -ext jpg .
pause

(Most of the ExifTool command arguments came from the Detecting Progressive JPG files thread on the ExifTool forum.)