I am searching all over the place to see if anyone elase has come across the following problem. I had images on my hard disk saved with a minimum of 300dpi. I have worked with them before, printed etc... I have come to look for one of my pics and when I found it, I find that it has been changed from a 300 dpi image to a 72 dpi. It has done this for all my images. I am trying to track what is causing this problem. I have loaded more images to the hard disk and they (so far) have remained at 300 dpi. I do not know exactly when this change occured but it seams rather strange to me. I am looking through all my logs (not the cut offs from trees) to try and pin point the problem and hopefully find a solution. In fact writing this now prompts me to look at my backup cds to check they are with the 300 dpi setting. I am using windows XP and have multiple image editing software. If anyone has come across this before, please let me know what happened and how you stopped it happening again. Also anyone else saving files on windows xp, you may want to check them to make sure nothing has changed!

Here is you problem : When you work with a picture and save it, the software put it by default at 72 dpi. To keep it at 300 dpi, you have to change the settings in the software. In photoshop is : Image/image size. And the just put 300 dpi. And that it. :~) - i hope it will help you. -

That is not quite true, most of the images have not been worked on and have just been loaded on straight from the camera. I teach people to use computers so I am well aware of the implications of opening in packages and just saving as is. If you open a 300dpi image in photoshop and save (without making any changes) it is still a 300dpi image. The issue is that previously saved files at 300dpi are now 72dpi.

Did you open the pics with the image-viewer from WinXP? This little bugger is well known for changing files without asking? Just an idea, sorry for not having better help.

Did the actual number of pixels change?

Working from memory at the moment, because I am at work. I think the image size is still 2832 x 2128 which is the recorded size on my camera at 6mb high and some at 2048 x 1536. All of the images where stored at those sizes but with 300 dpi. I do not use the WinXP image-viewer, but thinking about it (I will check when back from work) I have installed a new printer and it's own software ran once, picking up my folder of images. What the main problem is for me is that some program somewhere on my machine is altering the dpi of my images. It is not just confined to my photos either, this has also happened to my renders from c4d. I have the exact same software loaded on my machine at work and have no problems with it. All my virus profiles are up to date, although there is one virus I have just thought about! That virus, no virus checker can stop, it just happens to be my wife! I will get the lamp out and put her to the question when I get back. Sorry if I am ranting too much, just typing and thinking at the same time (dangerous combination, and yes sometimes men can do more than one thing at a time) I will go back and try to find out why it has happened and will let people know what did happen if I find it and how I got around it, just in case anyone else has the problem.

As long as the actual resolution (amount of pixels) doesn't change, who cares what DPI setting the picture is. It doesn't change the picture in any way. The only thing it does is saying how many of the pixels should fit in an inch when printing. So it's only important once you decide to print them, at which time you probably tell the software to print it at a certain size. Problem probably is that with some formats the DPI setting isnt't stored. Or some programs default the setting to 72 like DS said.

Yes, software related. Programs will save in 72, the monitor and web standard. You need to find the setting in youre programs and put them on 300. Only when you go for websaves do that in 72.

And you did not use Photoshops' "Save For Web" feature? From all that you've said I doubt that you did, but I'm asking anyway. I thought to ask because I once accidentally used this option to save 300 dpi tiffs to jpg, not realizing that "Save For Web" would automatically change the dpi to 72. I ended up have to redo the whole batch over again...

The images were 300 dpi when saved to the hard disk. I always make sure they are loaded correctly and open them in photoshop for a quick check. They are then closed and are still 300 dpi. Up until 5 days ago they were all in 300 dpi, now they are 72. There are no options to "save in a program at a particular dpi" None of the packages I work with "convert" the dpi when saving. When you store a file at 300 dpi it is 300 dpi unless you change the dpi, by either running in a batch converter or one by one. If you load an image from your camera onto your computer and the image is at 300dpi. At that moment in time, the image is saved as a 300 dpi image. If you open it in photoshop and then save, it is still a 300 dpi image. Photoshop does not change the dpi unless you ask it to. As mentioned before, this is not just my photos which I work mainly in Photoshop with. This happens with my 3d renders as well, most of them have not been opened with a graphics package since rendering and they have changed from a 300 dpi image to a 72 dpi image. I have done a quick check on the system and all the images have been modified (according to the computer) on the same date. I do know that I have not changed them because I have been too busy doing other things and my wife assures me that she has not been on the computer. I know it is not too important other than it causes me more work when it comes to printing my images. What I am trying to say here is, something is making a change to all my images and it seems to have done it as a batch (I do not have any batch file converters on that computer) If it has the ability to change the dpi then what is stopping it changing the size of images? I have not checked them all for the size. I do have a database of all my stored images, which includes original file sizes etc.. I need to spend some time looking at the data.

Again, the DPI number won't have any real effect on the image... a "300 dpi" image that's 1024x768 has the exact same resolution and total pixel count as an identical image that's "75 dpi." The only difference (in Photoshop) is in printing size and the image size percentage that shows up in the image titlebar (an image set to "75 dpi" may show the size as 100% when viewed on screen while the same image would say 25% if set to "300 dpi".) Just set the dpi correctly if/when you print or translate to another format and you'll be just fine.

Right, after taking a look at the files I find that it is not just the dpi that has changed. It has also changed the the size. What was 2832 x 2128 is now 2048 x 1536. This is not too bad for most images because they only need to be printed at 8 X 10 but some of the larger images were left like that because I needed them printed in a larger format on canvas (custom job I am doing for gallery) I'm not talking 1 or 2 pictures here, there are hundreds that are affected. The issue is not that I have to now change the dpi, some of the images will not be the right size for printing and to enlarge the images could cause additional problems (I do have backups). The problem is something has changed this on all image files without my knowing. If it has done it once, then what will stop it doing it again? If I was not so paranoid and did not have everything backed up I would really be up that creak without my paddle. Thanks to all that have contributed. I have no problem with changing dpi etc.. I do have a problem with my machine changing things without my knowledge. As I have mentioned before, I do teach people to use computers and one of my main packages is Photoshop so I do know about resolution and dpi. When you work on your personal computer with exactly the same software set up as your work computer and only the files on your personal computer are effected even though you have done the same things, then something somewhere is wrong. The only difference is that my personal PC is only using the standard microsoft firewall and Symantic AV. It just seems strange that it just the image files, I have been looking around the usual support groups for any particular viruses but up to now have not found anything with the same symptoms, hence my post here, all I was doing was trying to find out if anyone else has had the problem. I do not think it is a virus, just exploring that to rule it out.

Sounds like someone did a batch convert on your files :/ good thing you have backups.

Well, as I understand it that did not happen, the man has no batch done. So, it might be possibel a program you installed did the conversion. I know some programs that try to be master over the other progs and dont ask, just do there thing. But I think thats a bit far from what happens. Still thinking what this could have been. Ill be back.