Photoshop image resize looks terrible for an unknown reason -

Photoshop image resize looks terrible for an unknown reason -

original image file

http://fc08.deviantart.net/fs70/f/2014/173/1/7/4_charmander_by_monstermmorpg-d7ngugj.png

resized paint.net 3.5.11

http://fc04.deviantart.net/fs71/f/2014/173/5/6/paint_net_resize_by_monstermmorpg-d7nguje.png

resized photoshop cs 6 13.0 x64 , quality terrible

http://fc07.deviantart.net/fs70/f/2014/173/9/c/photoshop_resize_by_monstermmorpg-d7nguqn.png

any thought why , thought how solve annoying problem ? tried re-sampling options nil works

thank you

i think because indexed colour, gives limited palette.

go image - mode - rgb color

when rgb, should resize fine.

photoshop