PiBa on August 17th 2013
3843 views

DPI of some pictures changed after processing.

If i make a picture 100% its original size using PhotoResizeP100.exe some pictures keep their DPI settings and some dont.. They get 96 DPI..

This also happens when when using PhotoResizeD200.exe where the original images are 600DPI some images become larger (also in pixels), some shrink as expected.. All output images get the expected 200 DPI setting..

Has anyone seen this before? Is there a workaround?
Also is the forum the proper place to report this issue?

Thanks in advance for any reply. I can supply the images if needed. But this forum doesn't seam to support attaching a file..

Vlasta on August 17th 2013 0

Well, resolution can be specified in a .jpg file multiple times. Once in the .jpg header and once in an EXIF block. Picture Resizer works with the resolution in the header and ignores what is in the EXIF. If the initial file has different values in the header and in the EXIF block, the results may seem weird.

PiBa on August 17th 2013 0

Thanks for the fast reply, do you know if i could somehow work around this issue.? The images are made by different sources.. over witch i have no control, and when opened in my image editor seam to properly show as 600dpi. Do you know any (batchprocessing)program that could make the overwrite the jpg header with the exif information.?. Or 'force' PhotoResize to use the exif DPI data?

Vlasta on August 17th 2013 0

PhotoResize cannot currently use the EXIF data and I do not plan to add that feature.

Why do you need to work with the resolution anyway? It is usually a rather useless number.

PiBa on August 17th 2013 0

Ok, thanks for your reply.

The pictures are used to print them on paper, in which case the DPI's are used to determine how much cm they will be. Lowering the DPI and with that the resolution of the image is to reduce diskspace usage in the meantime. As they are stored for future usage also.. The original size of the images should be maintained when they are printed again. (the loss in quality is no issue.)

Thanks anyway for this great program.

Vlasta on August 17th 2013 0

I see. I would expect the printing application to use the resolution from the .jpg header, but anything is possible. I am sorry I could not be of more help.