DPI:
Dots per inch, or pixels
per inch. This is what we mean by the resolution of an image. The first thing
you need to know is that you can't add resolution to an image, but you can always
make a picture smaller, or decrease resolution. So, to be on the safe side,
start with more than you need, then reduce the finished image to 72 dpi (dots,
or pixels, per inch) at 100 percent.
Let's start with this image:
this image is 72 dpi and 1.5" X 1.5"
To change image size and dpi:
Resolution is DPI. You can change image size in either Pixel Dimensions or Document Size. Note constrain Proportions will keep the proportions of your image the same.
Also, make sure the image is in RGB mode, if you are resizing. It won't look so good if you resize an indexed color image:
do some samples on local drive>>>