cant get custom thumbnails to work in the grid, i put a link to a picture in the post but grid still displays my header image, tried changing all the settings on image source, still either nothing or the header, am i missing something?
Welcome to our forum.
Displaying custom thumbnail is a little tricky but it easy once you understand, go each of your post (which post you want to display via post grid) you will see the meta field settings for post grid, please see there is an input field "Custom thumbnail source" put there thumbnail image source(should be image url)
https://imgur.com/nk3L6kS
Once you done for all post you need to display cusotm thumbnail then back to post grid settings,
Layout settings > Media source
you will see there are media source with checkbox at left, drag and sort "Custom Thumbnail" at top and checked the checkbox at left, and then save/update post grid.
https://imgur.com/afMc7N3
you are done, just see the post grid, you will see feature image will replace with the custom thumbnail.
Hope you understand.
let me know for more help.
Regards