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deadshot May 5, 2011 6:04 AM

Preserving exif data mystery ??
I have just tried to enter a Nikon UK photo contest.
My first entry failed because although I had a file size of 1.9mb Nikon stated 2mb max, it was rejected as too big??.
So I reduced it to 1.7mb, that was ok but it was then rejected because I had not included the exif data.
I had changed the image size,cropped and sharpened it all in P/S/elements,so that must knock out my exif when I saved it I guess.
So can I make changes and still retain the exif, is that possible???
Also while I'm on this subject how do I deliberately not show exif data if that was my choice?.
Thanks for any help in this.

JimC May 5, 2011 6:24 AM

I don't use Elements, but with most Photoshop products, if you use Save for Web, the EXIF gets stripped out (so you need to use Save As instead).

If you're using Windows, you may want to try the free Irfanview to resize your images.

After opening an image (File>Open), just go to Image>Resize/Resample and plug in the dimensions you want to use (and you can plug in one side and let it compute the size for the other side if you make sure the box to retain aspect ratio is checked). Personally, I use the Lanczos algorithm for resizing (you'll see a drop down list of choices).

Then, after you resize the image so that the dimensions are smaller, use the File>Save As choice and give it a new filename (so that you don't overwrite your original), selecting JPG as the file type. When saving a JPEG file, you'll see a box pop up with a JPEG quality slider where you can select quality (so that it fits into their file size requirements). It will retain EXIF by default (you'll see a check box for that purpose on the quality settings screen after you select Save As).

deadshot May 5, 2011 7:00 AM

Thanks again Jim, you were spot on , it was the fact that I was using "save for web" .I started using it when I posted pics on this site and never realised it stripped out the exif.
I used it so that I could see the file size in the bottom left of the photo as I made changes to the file.
This time I used P/S elements> image resize >file >save as and it was accepted no problem.
Thanks for all the extra info.
Best wishes

deadshot May 6, 2011 4:58 AM

Hello Jim,
I'm back again.
I have noticed that when I resized in elements. I reduced the size to 1.94M saved as into my pictures but I have now spotted that the file size in my pics is 575KB.The 1.94 is shown in the resize window as pixel dimensions so perhaps it is not file size?
I know you said you didn't use p/s elements but what do you think has happened to the extra pixels.I used highest quality before saving.
I had Scale styles
Constrain proportions and Resample boxes all checked. was that the problem.??
I have done the same using save for web and the file size stays the same as I saved it minus the exif..
Yours puzzled.
PS I would like to carry on using P/E if possible but perhaps I wont manage to get the file size right if it doesnt show a true file size..

JimC May 6, 2011 5:31 AM

Dimensions in pixels (where width x height in pixels = total pixels) is not the same thing as file size in bytes. ;-)

Many users do that (confuse file size in megabytes with dimensions/resolution in megapixels, when they are two different things).

You can have an image that's 10 Megapixels (10 Million Pixels) that may only be 100KB (100 thousand bytes), depending on the format being used to store those pixels and the amount of compression being used if it's a JPEG image. One has little to do with another unless you're talking about a specific, uncompressed image format. You may have a 10 Million Pixel image that's 60 Megabytes in size if it's an uncompressed 16 bit TIFF file.

For example, if you save images in an uncompressed format like an 8 bit TIFF, then you have 8 bits (one byte) for Red, 8 bits for Green and 8 bits for Blue being stored at each pixel location. So, file size would end up being roughly 24 bytes per pixel (since red, green and blue values are being stored for each pixel location, using 1 byte of storage space for each color). In that scenario (uncompressed 8 bit image format), the file size for a 10 Million Pixel image would be approximately 30 Million Bytes (plus some overhead for other info in the header, etc.). Double that for a 16 bit TIFF.

Now, with JPEG, you're compressing the image to save space, so file size will vary with both content and compression amount (your quality slider when saving images using popular viewers and editors).

deadshot May 6, 2011 6:10 AM

So if I use P/E to resize to a desired max size of 2M it will have to be trial and error between My Pics and P/E jumping back and forth.
Where as Save for web it is easy minus exif.
It appears I will have to download irfanview and give that a go to get both the size right and the exif data preserved.

JimC May 6, 2011 6:17 AM

It's still going to be trial and error (as file size will vary with content type when shooting jpeg, as some areas will compress more than others). ;-)

But, if you keep your jpeg quality setting at around 80% with a solution like Irfanview (or around 8 with a Photoshop product) when saving a resized photo, in most cases, your file size will be within limits if the image has been downsized to 1024 pixels or smaller first.

deadshot May 6, 2011 6:26 AM

Thanks Jim,
With this competition it asked for 2M plus highest quality image and exif.Thats where the problem started.It looks like I sent them a highest quality 576Kb image :-) Dohh!
Anyway I'll bear in mind your advice and have a go with irfanview meanwhile.

VTphotog May 6, 2011 8:15 PM

With Irfanview, if you have d/l the plugins, you will have the option, in the 'save' dialog box, to save to a particular file size, which you can set. (uses the RIOT plugin) This allows you to choose both the photo size in pixels, and the file size in bytes.
RIOT (Radical Image Optimizing Tool) is also available in a stand alone version.
I do the same thing with Photoimpact, using the image optimizer when I save. Nice feature to have.


JimC May 6, 2011 8:44 PM

Neat. I haven't even looked at RIOT, even though I keep Irfanview and available plugins installed under Win 7, as I did with previous Windows releases.

The next time I boot into Windows, I'll take a look at it (I'm running in SimplyMEPIS 11 right now, which is a Linux distro that I'm currently using as my primary desktop Operating System after it went from Release Candidate to Final Release status day before yesterday).

Having a way to specify the desired file size would be a nice feature to have for saving images for forum posts here, I can remember seeing a few free products that were capable of doing that mentioned in posts here before. But, I've lost track of them and probably need to put together a list since this issue (needing to keep image size to a certain size or smaller) comes up often.

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