i created a form with Thumbnail columns. When I save the form with pictures in the thumbnail column, alle pictures are in the /SiteAssets/Lists/d574f925-34f0-4e15-8f7d-dc5d31f63fa6/picture.jpg. When I use the SharePoint form the SiteAssets/Lists/d574f925-34f0-4e15-8f7d-dc5d31f63fa6 is empty an my flow runs without erros. The correct path is /Lists/Listname/Attachments/id/picture name.
When I use the standard SharePoint form, the picture from the picture/image column is saved in /Lists/Listname/Attachments/id/Reserved_ImageAttachment...png. This is correct.
When is use the Plumsail form, the picture from the picture/image column is saved in /SiteAssets/Lists/d574f925-34f0-4e15-8f7d-dc5d31f63fa6/picture.jpg.