can't convert a progressive jpg to nonprogressive

[borell]

All,
I've tried "convert -interface None progressive.jpg nonprogressive.jpg" . While the identify command says the interlace is "None" (originally JPEG), photoshop and other tools says the jpeg is still progressive. Is there another switch I'm missing?

Thanks, Frank

[fmw42]

this seems to work for me (note the input image is before -interlace)

convert zelda3progressive.jpg -interlace none zelda3progressive_off.jpg

GraphicConverter tells me the input is progressive and the output is not progressive. I am on IM 6.5.9.0 Q16 Mac OSX Tiger.

[borell]

I'm on Windows with the same version. Photoshop still says its progressive.
I tried both versions of the command.

[fmw42]

I only have Photoshop CS (version and cannot figure out how to get it to tell me whether my image (that I created and tested above) is progressive or not. Can you tell me how? Then I will report back what my Photoshop says about the image I created as progressive and then converted to non-progressive.

[borell]

On the PS menu => file, save as, and choose a new filename. The following screen is JPEG options. One of the the three radial buttons is highlighted with the current state of your file; baseline(standard), baseline(optimized) , or progressive. You can choose to change at that point.

[fmw42]

When I create the progressive in PS and open it in GraphicConverter it says progressive, then

convert image_prog.jpg -interlace none image_progoff.jpg

and open it in GraphicConverter is says not progressive (normal).

If I open it in PS and try saving it again, it says progressive, BUT that is not what it is. The PS save window is remembering your last requested state and not reporting what it really is. I can find no Info window in PS that tells me all the characteristics of an image including whether it is progressive or not. But I only have PS CS.

You need to find another tool that will tell you the stats of the jpg. PS seems to lacking in this respect or I don't know how to find that info.

NOTE: in IM

identify -verbose image_prog.jpg

says Interlace: JPG

but

onvert image_prog.jpg -interlace none image_progoff.jpg
identify -verbose image_progoff.jpg

says Interlace: none