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What is PngCrush in iOS?
I'm having a doubts about image optimisation technique of iOS apps Pngcrush My doubt is, Is pngcrush built-in to xcode or do we need to explicitly download pngcrush tool and optimise our images? If we want to do it explicitly how can we achieve this?
This question may solve your problem: Skipping the 'CompressResources' build step for XCode iPhone apps
Another thing is there might chances that the PNGs are of type JPG's and the Extentation has been modified with png.