Re-scanning images to extract exif data

dpnow · February 4th, 2009, 06:00 AM

Hi,

For some weeks now we have had a problem with the installation of jhead on one of our galleries. This means that images uploaded for some time have not shown any exif data on the gallery. The jhead problem has been fixed and I have verified that it works, but I can't successfully use the re-scan function in admin to re-process the images that were uploaded when jhead wasn't working. How can I work around this?

Thanks,

Ian

Chuck S · February 4th, 2009, 08:14 AM

well you can rescan however if you use jpegtran to strip the headers off files also it is quite possible the exif information does not exist anymore so you would have to reupload the photo possibly through edit photo.

dpnow · February 5th, 2009, 02:45 AM

Quote:

Originally Posted by Chuck S

well you can rescan however if you use jpegtran to strip the headers off files also it is quite possible the exif information does not exist anymore so you would have to reupload the photo possibly through edit photo.

How can I discover if JPEGTRAN is set to strip the headers? Why would I want to do this in any case?

Thanks,

Ian

Chuck S · February 5th, 2009, 09:56 AM

well tell me this.

Try downloading from your gallery a regular image already processed that is not showing exif that you sure had exif. Reupload the image is exif extracted?

Next upload a regular image that has exif from your camera etc that is new is exif extracted?

Your answers to these questions will let me know how to answer.

Basically if new images are being extracted exif fine but old ones cant then it tells me that the header data has been stripped.

dpnow · February 10th, 2009, 05:40 AM

Quote:

Originally Posted by Chuck S

well tell me this.

Try downloading from your gallery a regular image already processed that is not showing exif that you sure had exif. Reupload the image is exif extracted?

Next upload a regular image that has exif from your camera etc that is new is exif extracted?

Your answers to these questions will let me know how to answer.

Basically if new images are being extracted exif fine but old ones cant then it tells me that the header data has been stripped.

Hi Chuck,

I downloaded a picture that failed to show exif in the gallery originally, then re-uploaded it as a new image (re-named). The exif for the re-uploaded image now appears normally.

All other exif images newly uploaded are showing exif normally.

However, I can't get the images that originally failed to show exif to show the info. I have tried re-scanning the files using the 'Check here to rescan photos and save EXIF information.' option.

Ian

Chuck S · February 10th, 2009, 08:47 AM

Ian

check then in your database for that photo there is an exif column what does it have entered in that column 1 or 0 for a photo that does not show exif that you know has exif?

You can possibly in image-inc.php try this line

Code:

Content visible to verified customers only.

maybe change to this?

Code:

Content visible to verified customers only.

dpnow · February 18th, 2009, 11:23 AM

Hmmm..., this is what I have:

Code:

Content visible to verified customers only.

It's not the same?

Ian

Chuck S · February 18th, 2009, 12:47 PM

what version of Photopost are you using?

dpnow · February 20th, 2009, 10:00 AM

Quote:

Originally Posted by Chuck S

what version of Photopost are you using?

We're still on 6.0...

Ian

Chuck S · February 20th, 2009, 10:25 AM

oh well maybe you want to try downloading and using a clean 6.2 and see what happens.

dpnow · March 17th, 2009, 03:46 PM

Quote:

Originally Posted by Chuck S

oh well maybe you want to try downloading and using a clean 6.2 and see what happens.

Hi Chuck,

Finally got around to upgrading to the latest version. Problem now is that I have lost all the user option controls under the picture - edit photo, show exif, add favorite, report photo, etc.

The layout should be similar to:

Kite Surfer in Tramore - Four Thirds User photo gallery

but here is what it looks like on DPNow:

http://dpnow.com/galleries/showphoto.php/photo/10895

Ian

Chuck S · March 17th, 2009, 08:06 PM

They are there look in the upper right corner of the picture window.

The Photo Options

dpnow · March 18th, 2009, 02:58 AM

Quote:

Originally Posted by Chuck S

They are there look in the upper right corner of the picture window.

The Photo Options

OK. Don't get me wrong, I am relieved that they haven't entirely disappeared, but I am less than enthusiastic about this as I will now have to notify all my users about the change, and the new arrangement is really not intuitive.

And unfortunately, the upgrade has not fixed the problem whereby many images that definitely have exif data are not showing this data in the gallery.

For example:

test only - DPNow Photo Gallery

Thanks,

Ian

Chuck S · March 18th, 2009, 09:57 AM

Feel free to send proper sign in data for us to look but these are my thoughts.

Buffy - ReefTalk Gallery

1. Exifdata if an image has it on upload will be extracted.

2. Exifdata is only going to be rescanned from a photo in admin if it has exif data still.

You would have to provide explicit details where you think photos still have exif etc on your site and I would have to do some testing.

I am using an unaltered 6.21 code. I just went through my gallery admin and rescanned exif and it extracted and saved from images that I am seeing.

Chuck S · March 18th, 2009, 10:00 AM

Your exif information shows on that photo if I process it

exiftest - ReefTalk Gallery

I simply think given that maybe your jhead processor is not working on the server?

dpnow · March 18th, 2009, 12:38 PM

Quote:

Originally Posted by Chuck S

Your exif information shows on that photo if I process it

exiftest - ReefTalk Gallery

I simply think given that maybe your jhead processor is not working on the server?

Hi Chuck,

Just to recap, all new exif-tagged images work fine at upload. The issue is pre-existing images that were not processed correctly when we had a period when our jhead processor was not configured properly.

The example I posted is one that was uploaded a while back, when jhead was not working for us. I don't really want to have to re-upload all the images in question (several hundred!).

Ian

Chuck S · March 18th, 2009, 12:47 PM

dpnow well there is your issue.

see if you have previous images and jhead was not working well those old images do not any longer have exif info. Thats the heart of the issue. To extract exif the image needs to have exif. You take a prior image that had exif and process it without exif or where something is faulty I would assume the image info is getting stripped.

I ran the scan database exif thing and it works fine as its the same process and function we use when you upload a new image. Example take the image that is on your server that is already uploaded from a previous old photo and reupload it. You will see NO EXIF thats because there is none so there is nothing for jhead to extract. Thus thats why the rescan can not extract anything because your images do not have any information on them anymore.

dpnow · March 18th, 2009, 02:48 PM

Quote:

Originally Posted by Chuck S

dpnow well there is your issue.

see if you have previous images and jhead was not working well those old images do not any longer have exif info. Thats the heart of the issue. To extract exif the image needs to have exif. You take a prior image that had exif and process it without exif or where something is faulty I would assume the image info is getting stripped.

I ran the scan database exif thing and it works fine as its the same process and function we use when you upload a new image. Example take the image that is on your server that is already uploaded from a previous old photo and reupload it. You will see NO EXIF thats because there is none so there is nothing for jhead to extract. Thus thats why the rescan can not extract anything because your images do not have any information on them anymore.

I think we're going around in circles a bit here

I have established that the pix that were uploaded when the jhead settings were wrong - still retain their exif data. I can copy them and re-upload them now and they show the exif data no problem. But re-scanning them fails to show the exif data...

So there is definitely exif data in there, but the re-scan process is not extracting it.

Ian

Chuck S · March 18th, 2009, 03:55 PM

Well I have triple checked everything and it works.

So I went to one of the photos you say should have exif info and downloaded the large image and indeed I uploaded it.

20080120100112-digitalbilleder-055-10-gold - ReefTalk Gallery

The image does not have exif information so that is the issue that I see.

In fact I just did the ultimate test I truncated my entire exif table and then ran scanbd to repopular the exif and it worked fine.

See this is one I uploaded earlier that had exif

exiftest - ReefTalk Gallery

This is one I uploaded from your site that you said had exif in an earlier link but it indeed does not.

20080120100112-digitalbilleder-055-10-gold - ReefTalk Gallery

The scandb repopulated all my exif data

dpnow · March 18th, 2009, 06:09 PM

Well, here is an example that demonstrates my case:

The image here does not show any exif data in the gallery:

Father and daughter - DPNow Photo Gallery

I locate the image here:

http://dpnow.com/galleries/data//547/P4279403.jpg

I then downloaded it and in Windows preview, you can see that it has exif info.

Ian