Hi,
I am wanting to submit a photo to a photographic magazine for comment. They require Jpeg images and 900 pixels along the longest dimension. If I edit with photoshop and go to image size my 4 MB photo has 3000 pixels (105cms)along the longest dimension at 72ppi. So I tick resample and make it 900 pixels - the image then goes to 31 cms along the longest dimension. However if I submit this at 72 ppi surely it would be unsuitable for printing. Hence if I untick the re-sample box and make it 300 ppi it shrinks to 7 cms. Thought this would be too small for a photographic magazine to print.
What am I doing wrong here? Would a magazine really want an image like this. Should I resample and make it larger - but that would be defeating the purpose.

Do exactly what they ask for. The pixel dimensions are all that really matter. Dpi is flexible and only a function of the display size. However, it can't hurt to ask them if that's what they really want and point out that it's a very small image. But maybe they only want a very small image.