Apple devices take photos in Apple’s own file format, HEIC. Some programs recognize HEIC files, some don’t. Sometimes a program only wants a JPG (or JPEG) photo.
Google Drive can store and preview an HEIC image. It recognizes it as an image and will show it to you, but it won’t let you use it in Docs or Slides. The blog software (WordPress/Campus Press) doesn’t recognize it at all. WeVideo recognizes and supports it, it can use HEIC files just as easily as any other file format.
If you have HEIC pictures and you need to convert them to JPG/JPEG files using a Chromebook you can use a free online tool; heic.imobie.com
If you have a Mac you can check out the iMazing HEIC Converter tool.
Here is a 1-page guide to using imobie on your Chromebook to convert your HEIC images to JPG files…