Resizing a sprite into negatives by dragging the transformation handles in the layout view behaves as expected (the sprite becomes mirrored).
Bug 1:
Resizing a sprite into negatives by entering a negative value into the properties panel does not behave as expected (negative value gets automatically set to 1).
Bug 2:
Resizing a sprite into negatives by using a set size event does not behave as expected (sprite size doesn't change).
Sample capx: dropbox.com/s/72uo8b90gm63937/resize.capx
C2 r95 / Win7 64bit / Latest Chrome