For some reason the failing base64 decoded .png
is invalid. If you download the image and re-save it the filesize is different.
I see 237 bytes for the original verses 409 for a re-saved copy.
This can be confirmed with the pngcheck
tool.
Z:\pngcheck-2.3.0>pngcheck.exe original.png
original.png EOF while reading CRC value
ERROR: original.png
Z:\pngcheck-2.3.0>pngcheck.exe re-saved.png
OK: re-saved.png (24x24, 32-bit RGB+alpha, non-interlaced, 82.2%).
Using the following valid re-saved.png
base64 encoded data fixes the problem in IE8.
background:url(data:image/png;base64,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);
I assume Chrome and Firefox are more lenient with the CRC.