Original sentence: Because of different or more exhaustive search strategies being used, some other programs may give better results by several percent on certain files.OptiPNG, AdvanceCOMP and Ken Silverman's PNGOUT, for example, can sometimes outperform pngcrush in regards to PNG file sizes, although the time taken (and in some cases, the required manual labour on the user's behalf) to reach the result is usually increased.pngcrush may not always generate the smallest PNG file possible
Edited sentence: Many other programs can reach better results by several percent.OptiPNG, AdvanceCOMP and Ken Silverman's PNGOUT, for example, consistently better pngcrush in regards to PNG file sizes, although the time taken (and in some cases, the required manual labour on the user's behalf) to reach the result is increased.pngcrush seldom generates the smallest PNG possible