aseitun

The rendering of true coulor+alpha channel (32 bit bitmap) of PNG images is correctly done only by Firebird/Firefox/Mozilla and Opera 7 browsers. On the contrary, IE6.SP2 is able to render PNG true (16.8 mil, 24 bit) colours “only” without alpha channel transparencies. Otherwise, they are rendered on an unavoidable grey-opaque background. Unfortunately, all the MSIE tricks – or hacks – that have been so far proposed miserably fail on all Win OS platforms. It’s useless to further increase the entropy of the debate on this issue. It seems that the various “treatments” (PHP included) had not been tested sufficiently on IE6.SP2 (! important: the security SP2 for IE5+ and for IE6 have been detrimental on this account, but not all the MS OS are systematically upgraded and patched…). Thus, IE6 can only die, or drastically be changed (hopefully, uh!). Therefore, cross-browser background transparency is limited to 8-bit (256 colours) GIF or PNG images having one (or more) 100% or on-off transparent colours. This can be easily obtained through Fireworks, XaraX, Gimps or PaintShop (and other few nick progs). The resulting GIF and PNG transparent versions of the same image are perfectly superposable and visually equivalent, since the gamma autocorrection of PNG algorith (absent in the GIF one) is also disabled. Since the PNG conversion is not licensed (as the GIF one is) and is able to produce smaller true and 256 colour files (e.g., a 256 col 8.534 Kb GIF becomes a 7.617 Kb PNG), it’s officially recommended by W3C. Conclusion: no solutions or miracles, but mirages (and time-consuming disappointments) for IE6, at least up to now.