If the stem u have right now is 26 mm standard clamp then yes u can put the yellow one w/o any problem.

No idea if the stem u have is 25.4 or a 26 mm clamp stem, u need to find out yourself using a caliper. If what u have is 25.4 i wouldn't try to put a 26 mm handlebar in there, specially because the stem you have doesnt look like a super duper one at all, and who knows what could happens if you force it too much.