the new high compression is good for slow/paid networks, but png are not compressed, what to do? (I will answer to myself)
as a workaround to convert png images to jpg images that are compressed, select your png image, tap the edit button, then tap the save changes button and tada! your image is converted to jpg and compressed as usual!
it’s a shame that some of us as user of 0.301.1 still can’t use edit feature 
