setAlpah issues

[shalevBA]

hi guys 
im having an issues with opacity of a picture in the touchGFX from some reason its giving me only tree option: 
solid (255) or invisiable (0),
and the third option is between which is staying on the same opacity all around the scale between 1- 254
so its dosent metter if im choosing 170 or 254 its will give me 50% opacity..
how can i solve this issue? 

[shalevBA]

solved by using different photo