This makes life much simpler for my son since he now knows when he resizes the photo to his desired size, if he has to enlarge it, it's no good. The publication software imports the image at a size which is dependent on the DPI setting. However, when my son puts together publications himself he uses preview to change the DPI of each photo to 300 dpi before importing it into his publication software. The publisher (or rather the person working at the publisher, who is a friend of the owner of the restaurant and possibly in training) who should really know better, asks for photos at 300 dpi, my son understands what Larry is saying about DPI, but there is no point in arguing with these people and changing the DPI setting keeps everything sweet. He's the marketing manager at a local restaurant and often is involved in preparing literature and also working with the publishers who also prepare the companies literature on occasions. I believe my son uses it regularly for two reasons. I believe preview can set the DPI tag, the adjust size option has a resolution setting which appears to do this. The answer to their question is to do the math - thee is no setting to accomplish what they want and if someone mistakenly tells them there is it is a disservice to the OP How do I find the dpi of my photo I need at least 300 dpi

Unless people understand this they are likely to get poor or unpredictable results - if they send a photo that is going to be printed at a size making it 50 DPI thinking tha t because they changed this meaningless field to 300 they are going to get bad results where as if they understand that they can not set the DPI then they will get good results again the OP's questions is only about the DPI of the finished image - noting to do with irrelevant settings that have no effect on the actual results of printing the photo I know you guys love to argue but the OPs question is how to change the DPI of a photo and you can not do that because it is the answer to a calculation - it is not a setting and even though there is a setting (as I explained) changing it has nothing to do in any way with the DPI of the image - that is a mathematical calculation - changing the setting is like changing the acreage on on a Plot plan - it does not change the acreage of the plot nor does changing the home square footage printed on a set of house plans change the actual square footage of the house- the house is still what it it and the DPI (remember it is Dots Per Inch) on the image is what it is no matter what the setting says

How to find dpi of jpg