When an image is inserted into a google doc, or blogger site, or even google photos, it gets automatically hosted at googleusercontent.com. If you right-click and get the image address you will find the url is that domain followed by a very long id string. While most browsers do read this properly as an image, some gadgets and tools, require inserting images that have a .jpg, or .png extension.
This is actually surprisingly easy, but not all that intuitive. Basically just add a "?.jpg" to the end of the url from googleusercontent.com and it will work.
Here is an image from my photos.google.com. I just opened the image, and then right-clicked and got the image address.
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9knzokJGoWmC6CYv1s0iCpgd5Vo-KjrQgjJlUoiTN6_RGVPw-HZ6KjIZqfyOHt2Ue82VBmnjHVVxGf4fSmgOnOwR0DIzERppdgV1qUN3v3CmAoozCsqkcaueCI3uATP4slk-jftmD9SU5/w709-h945-no/
I can paste that url directly into the browser and it will show just the image, but if I want to embed that image into a gadget, then I might run into an issue if the gadget requires a .jpg extension at the end. All that needs to be done is add a "?.jpg" to the end of the url, and you now have a url that you can use in your gadget.
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9knzokJGoWmC6CYv1s0iCpgd5Vo-KjrQgjJlUoiTN6_RGVPw-HZ6KjIZqfyOHt2Ue82VBmnjHVVxGf4fSmgOnOwR0DIzERppdgV1qUN3v3CmAoozCsqkcaueCI3uATP4slk-jftmD9SU5/w709-h945-no/?.jpg
