Cannot view jpg's in DPP 4

[cdmazoff]

Hi.. This is recent.  I work in RAW export to TIFF, open them in photoshop CS5 and finish them as jpegs.  Up until last month (September 2018) when I opened any directory with CR2, TIFF and jpgs in DPP 4. 8. 30 ALL the files had usable thumbnails. I can still open jpegs I made in August 2018 in DPP but not newer ones.  I have not changed anything.

Now, the jpegs display as small thumbnails with a ? and "Unsupported Image"  and will not display in preview or open to edit in DPP..  

Can anyone explain this bug to me?

[RobertTheFat]

If the JPEGs were created in DPP, then you apparently have a legitimate complaint about a bug in DPP. But as I read your workflow, those JPEGs would seem to have been created by Photoshop. If that's the case, your beef is probably with Adobe, not with Canon.

[cdmazoff]

Thanks Bob.  I hear you.. But the thing is that all the jpegs made this way since May 2018 open in DPP ... except for the last month!!  Maybe it's a Windows  7 update thing.  When is DPP 5 due out?

[cdmazoff · Accepted solution]

Solved!  Someone on the retouching forum at DPR looked at my jpegs and noticed that the bad ones used progressive.. The good ones didn't... So, I resaved as baseline optimized and no problems.  I wonder how that switch happened!  

[RobertTheFat]

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@cdmazoff wrote:

Solved!  Someone on the retouching forum at DPR looked at my jpegs and noticed that the bad ones used progressive.. The good ones didn't... So, I resaved as baseline optimized and no problems.  I wonder how that switch happened!  

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Do the "progressive" image files violate the JPEG standard? If so, then Adobe has a problem. If not, then Canon has a problem. Or so it would seem.

If the question has no definitive answer, then is the problem a lack of precision in the JPEG standard?