DumpAllPNG and DumpAllJPG almost the same

[realTobby]

• make a more generic function and give over the extension. so it would be actually possible to fitler trough more than 2 image formats.

[realTobby]

solved this issue in the commit https://github.com/xSillusx/ImageScraper/commit/30d1ca9a42909924efb8f3f1ad1fcd31ba35897f