Just replace source with the URL (in quotation marks), then add an optional description (alt_text), 0 to 3 for sizing to indicate how you want it to look (0 to fit the cell, 1 fills the cell, 2 is the ...
With any software, the more you use it, the more hacks and shortcuts you discover, and never a truer word has been said when it comes to Microsoft Excel. What's more, as the program evolves, you add ...