When is a JPEG file not a JPEG file?

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ChrisGreaves
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When is a JPEG file not a JPEG file?

Post by ChrisGreaves »

(curiousity value only)
Brainwave: why don’t I copy my PrtScr images of Google maps to my camera so I have a cheap map-reading device for my trip to Peterborough. Brilliant!
Except for the hurdles:-
DSCN1446[2].jpg
(1) Save to camera from MSPaint is thwarted by the camera “You can’t save here. Please choose another location”
DSCN1446[3].jpg
21) Copy/Paste a PNG or a JPEG file (the JPEG file savedAs by MSPaint) is thwarted by the camera “Your device might not be able to play or view this file”.

I understand that the Nikon Coolpix (a.k.a. El Cheapo Camera) is protecting its turf, and that the terms “PNG” and “JPEG” probably refer to a generic type of encoding, but is that it?
We have not only a zillion picture formats (BMP, JPEG, PNG, ...) but even within a single format Not All Formats Are Created Equal?
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HansV
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Re: When is a JPEG file not a JPEG file?

Post by HansV »

There *are* different types of .jpg files.

In the first place, cameras usually save photos in EXIF jpg format, while Microsoft Paint saves images in JFIF jpg format. Most cameras will not recognize JFIF images. See Exchangeable image file format and JPEG File Interchange Format.

Companies may also add brand-specific information and refuse to display images that do not have this information.
Regards,
Hans

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ChrisGreaves
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Re: When is a JPEG file not a JPEG file?

Post by ChrisGreaves »

HansV wrote:There *are* different types of .jpg files.
Thank you, Hans, for confirming my thoughts.
I have d/l the pages and will study them tonight.
And I promise I will not :ranton: about how we haven't made any progress since the distinction between keypunch combinations ASCII and EBCIDIC coding for 80-column punched cards. :grin:
That's a hole :evilgrin: other issue.
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ChrisGreaves
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Re: When is a JPEG file not a JPEG file?

Post by ChrisGreaves »


Well, thank goodness that weekend is over. It rained Sat/Sun so I had to stay in and read the articles (grin!).

I found out something else:
Same camera, same computer, same photos ...
I can use Windows photo-Viewer and left-right through a set of photos that have been copied (Ctyrl-C, Ctrl-V) from the camera to my hard drive.
But I can't do that to the images that are ON the camera drive.

Likewise (I think I remember this correctly) I can MSPaint-edit the images on the computer, but not when they are on the camera.

It's as if the software that manages the cable (well, in the camera end of things I guess) refuses to honour any commands except "copy" and "paste" and the ilk.
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HansV
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Re: When is a JPEG file not a JPEG file?

Post by HansV »

Sounds plausible, and not unreasonable...
Regards,
Hans

PJ_in_FL
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Re: When is a JPEG file not a JPEG file?

Post by PJ_in_FL »

ChrisGreaves wrote:...
I found out something else:
Same camera, same computer, same photos ...
I can use Windows photo-Viewer and left-right through a set of photos that have been copied (Ctyrl-C, Ctrl-V) from the camera to my hard drive.
But I can't do that to the images that are ON the camera drive.

Likewise (I think I remember this correctly) I can MSPaint-edit the images on the computer, but not when they are on the camera.

It's as if the software that manages the cable (well, in the camera end of things I guess) refuses to honour any commands except "copy" and "paste" and the ilk.
As you found previously, the Windows drivers for this camera prevent any write access to the storage on the camera, and I'd expect that's the reason WPV cannot access the files on-camera, as it tries to open the files Read/Write. WPV can, for example, rotate and save the changes, so it wants R/W access to the files.
PJ in (usually sunny) FL