In 4.9 a picture marker symbol on a MapView rotated with the view. So we watched the mapview rotation and updated the symbol rotation accordingly to have a screen aligned image in any rotation.
In 4.10 a picture marker symbol is always displayed unrotated and aligned to the screen by default.
Before making changes to our code, i'd like to make sure that this is a feature and not a bug.
Side question for esri staff is - Could you make this behavior customizeable with a property on the symbol class?
We changed the behavior you are describing at 4.10 to be consistent with other ArcGIS products.
At version 4.10, the markers are screen-aligned, so if an arrow points straight up, when the map is rotated, it will continue to point straight up. Similarly if an angle is applied to the arrow to make it point to the right
then as the map is rotated, it will continue to point to the right. The one exception to this rule is when a rotation is present in Visual Variables at which point, the marker will point in the map-aligned direction specified by the visual variables.
Hope this helps,