Our system can generate thumbnails for files up to 250MB, depending on how the file is structured. When a file has a large number of layers or high resolution, it’s possible our system will fail to generate a thumbnail.
If your file didn’t get a preview image; you can click on "Regenerate thumbnail" to re-start the process of generating a thumbnail. This works in most cases, but if the file is too complex or heavy and this option doesn't work, you can upload a thumbnail to the file instead. Simply create a smaller version of the image in .png format and upload the thumbnail by clicking on the image. Now, find “Thumbnail” in the menu to the right, and click on the pencil icon and select “upload thumbnail” – this will add a small preview of the image in the grid. The recommended size is 500px width.