Let Photoshop to do the calculations. In the dialog box image Size in Photoshop, there is a button that many users ignore. It’s called Auto and here is how it works; You indicate the desired image quality (Draft, Good, or Best) and Photoshop will make the calculations for the proper resolution of the image based on your selections.
So, here is …

This is a quick tutorial on how to resize an image. Resizing an image is useful when you want to send it by email, upload it on a website or just keep the file size small.
First go the top tool bar of your Photoshop UI and choose Image-> Image Size. A dialogue box will open and what you want to do …