While it has always been possible to add images to any inside of your Google Docs spreadsheets, you can now insert images and icons inside individual spreadsheet cells as well.
To add an image to a cell, highlight the cell, click F2 to enter the formula mode and then type =image(“URL”) where URL is the public web address of that image.
Google Docs, by default, will scale the image to fit inside the area of the selected cell but you may change the default settings by adding another parameter to the image function.
For instance, a formula like =image(“URL”, 2) will stretch the image to fit inside the selected cell while =image(“URL”, 3) will insert the image into the cell at its original size.
If you are getting parsing errors, you are either using a non-existent image or you may have missing adding quotes around the image URL inside the image() formula.
Refer to the documentation for more details.