This is just a very simple guide that would show you how to resize your images without losing its proportions.

First, Right Click the Title Bar of your Workspace.

With that, You should see these options . . .

Select Image Size. It shall give you this window.

With this window, you can set your preferred Width or Height for your Image. Please take not that the Constrain Proportions option must be Checked for you to maintain the proportion of your image. In this case, if you’ll be changing the width of your image, the height shall be automatically adjusted and vise versa.

After doing this, you should be able to have your image resized without having problems on its original height or width. Hope this helps.