PunyPNG allows multiple image uploads of each file size no greater than 150KB, and supports only PNG, JPG, GIF, Animated GIF and requires Flash installed.All the compressed can be downloaded at once as a zip file, a preview of the compressed image can also be seen by hovering the mouse pointer over the image file name.
Features :
- Multiple Image Uploads
- Supports PNG, JPG, GIF, Animated GIF image formats
- Highest compression, compared to other common online image compression tools.
- Preview of your puny(compressed) image.
- Compression of transparent images upto 35%
Note : All uploaded images are deleted within 15 minutes of upload, so worries of privacy aswell.
A wordpress plugin like WP Smush it, for PunyPNG can make it more easier for bloggers.