4 pngs were created, each 1000x1000 pixels in dimension 1 png, 80x80 pixels in dimension. It uses the same image as the one used in png-transparent-tinyimage.png
Images can be found here: https://dl.dropbox.com/u/416403/png-test/png-test.zip
- png-image.png
- full size photo
- png-one-color.png
- fill of one color
- png-transparent-tinyimage.png
- 80x80px photo in center, surrounded by transparency
- png-transparent.png
- entirely transparent png
- 80x80-photo.png
- 80px x 80px photo, copied image from png-transparent-tiny-image.png
before optimization
14993 Mar 14 11:24 80x80-photo.png
1124215 Mar 14 11:08 png-image.png
5232 Mar 14 11:07 png-one-color.png
26244 Mar 14 11:08 png-transparent-tinyimage.png
6196 Mar 14 11:17 png-transparent.png
After optimization ( optipng -o7 *.png)
Note: optipng took ~2 minutes to work on these 4 pngs.
14345 Mar 14 11:29 80x80-photo.png
1053914 Mar 14 11:21 png-image.png
1070 Mar 14 11:21 png-one-color.png
23619 Mar 14 11:21 png-transparent-tinyimage.png
1083 Mar 14 11:21 png-transparent.png
Although the image was the same, the 1000x1000px png-transparent-tinyimg is ~2x the file size of it's 80x80px counterpart. This means that dimensions, as well as pixel content does matter.
The 1000x1000px png-transparent-tinyimg compressed better: ~9% compared to to the ~4% achieved with the 80x80px counterpart.
For an image almost 12 times larger in pixel dimensions than 80x80-photo, the png-transparent-tinyimage is only 1.6x larger in file size.