Because it is not a declaration set specifically for retina images. Try taking
out the resolution part which you have separated with a comma which means "or".
Your declaration basically says...
All screens 320 to 568 px with a ratio of 2 OR all screens with a
min-resolution of 192 dpi
Best,
K
There is something I don't understand, I have the following MQ;
@media only screen
and (min-device-width : 320px)
and (max-device-width : 568px) and (-webkit-min-device-pixel-ratio:
2),(min-resolution: 192dpi) {
Within the MQ I have a style which consists of a x2 image & for testing