Slight optimization in DS graphic files

I compressed some PNGs used on the system using Adobe Photoshop's Save to Web and Devices function.
It's not a huge file size difference, but it could free some resources at loading, many of them were 8KB in size and were compressed to 1KB without any loss in quality.

https://drive.google.com/file/d/0B7r8MDH...sp=sharing

I uploaded the entire DS folder because I was editing these files when my internet connection was off and I don't remember what files I edited...

Only JPEG's I didnt compress because this function could drop the quality of the image in the compression process.

Thanks SWAT for this great work!