Watch out for large file sizes – Whenever you add images to Excel you must remember that these can really increase the file size of your workbook if you choose a large image.Improve readability by formatting – Another way to improve readability is to hide cell gridlines and apply solid color shading to cells that contain data.If your foreground is mostly white or bright colors then you can use a dark image. If your font color is black and you are using a lot of dark colors on your sheets, it makes sense to choose a very light colored background image or make it semi-transparent with an image editor. Improve readability by choosing your picture carefully – It’s a good idea to use an image that provides a lot of contrast with your main content to make it easy to read.Page Layout > Delete Background Extra Tips – Adding a Sheet Background Image
