Adjustment Layer Effects Lost when Merging Layers

[mjerryfuerst]

I scanned a drawing I made as a .jpeg, opened it in PS CS4, converted the background to a layer, added a curves adjustment layer, and when I try any of Flatten Image or Save as Jpeg the results disregards all or part of the effects of the adjustment layer. The same happens for a levels adjustment layer . I have attached the original jpeg and the .psd with the curves adjustment layer.

 

[peta62]

I do see some difference between pictures saved with and without adjustment layer, although the difference is smaller than what I see directly in Photoshop. But it may be due to colour settings and/or different software used to check, I know from experience different picture viewers show different colours.