Well that's not simple as it seems to be. Dragging the image to the URL doesn't work any more. So the only way is to open the browser developer tools (ctrl+j or ctrl+k) and locate the element to extract it's URL. Then you can insert it using the URL you found out.
First, you will not be get banned for using a built-in function like IMAGE(url) as the request is made from Google Servers and it's made anonymously. Anyway, if you want to "freeze" the images on your spreadsheet try the following
Select the range having the IMAGE(url) formulas
Paste as value only
For the above procedure you could use the contextual ...