It depends on how old the marketplace item is. Only newer ones (last two years) were saved with metadata for height and width. This data is expressed in terms of integers, corresponding to grid units. This works perfectly for square gridded maps. Unfortunately, isometric values do not mathematically correspond to these integer values. It's possible there will be an update to this in the future (I would hope), but currently, isometric grids are an introductory, and (I would say) experimental feature. More technically, there are three possible values a marketplace seller can give to a graphic's H/W values: null:null This may not be possible to enter on newer sets. 1:1 (default on newer sets) #:# (or rather, specific integers, the newer preference) These values give different behaviors when dragged: null:null will drag in 1u:1u or 3u:3u depending on layer, and alt will constrain them to native aspect ratio. Intended size is not possible, of course 1:1 will drag in at 1u:1u, regardless of layer or modifier keys. My guess is that this has something to do with not setting a value, but leaving it at the default. #:# will drag in at intended size, as will alt When I use the value u above, this refers to square grid units. Please note, the above is based on personal testing and investigation with the browser's Inspector tools It may be inaccurate in its assumptions. TL;DR: Isometric grids are a new, developing feature, and are not yet mathematically supported by the marketplace