try duplicating each png a few times. I've done the same thing to slow down the animation. So if you have 4 png for example and copy each on so that 4x3 = 12 this will slow down the visual animation. You can tinker around with this until you get the result you want.
Select your character on the left hand panel (not on the game scene!). Then on the right hand side you will see different animations. If you hover on an animation type, let's say "Default", then you will see a pencil. Click on that. Now you will see the animation editor. On the bottom right you can see the speed, adjust that and with play you can check it out. Trick is that you have to stop and re-play the animation every time you change that speed -- hope this will be fixed... When you are satisfied, close off the window and all should be fine.
Thanks A Lot i did it ... Another question Can we add more action (platform game) example : Block - rolling - sliding ...