Add placeholder flag when image widget has empty _image array#5228

skosarin wants to merge 1 commit intoapostrophecms:mainapostrophecms/apostrophe:mainfrom

skosarin:sk.fix.archived-image-resulting-in-no-placeholder-and-errorskosarin/apostrophe:sk.fix.archived-image-resulting-in-no-placeholder-and-errorCopy head branch name to clipboard