When changing sizes, always be sure to have 'Constrain Proportions' checked off.

When changing sizes, change it by Pixel Dimensions or Document Size. Image Size allows you to change both the document and actual image size. Image Size menu is accessible by clicking on the Image menu button and clicking on Image Size: Know the difference between Image Size and Canvas Size below: Looking at your Image Size and Canvas Size menus allows you to see the size of your image, edit your image and change your document size. Web media: Resolution should be 72 with color mode being RGB as RGB is the color mode for all computer screens Image Size and Canvas Size Menus: Print media: Resolution should always be 300 with color mode either being in CMYK for color or Grayscale for Black and White printing Here are some general guidelines to follow for each: Setting up your document will be different for print and web files.