Learn more about how the image block works.
Answer:
There are some images that have a different file format. The Letterhead image block accepts image file formats like JPEG or PNG.
If the image file format is HTML, then our image block won't accept it, and you will get an error. When you come across this issue, we recommend that you download the image to your computer from the website, and then upload it to Letterhead.
If you still get an error after doing it, please take a screenshot or video and submit a ticket via Contact Support.