Los usé y los cambios que realiza son fabulosos! Gracias!

Good question. Both JPEG and PNG32 use 24-bit color, so you won’t lose any color depth with a PNG32 (or a PNG24). PNG32 would allow alpha transparency, where JPEG does not support any transparency, so it is possible to create some unique effects with partially transparent photographs.

However, JPEG is uses a “lossy compression format” and will nearly always produce smaller file sizes than a PNG24 or PNG32, but the smaller file size is at the cost of some detail in the photo. JPEG also gives you the ability to control the lossiness, or the level of compression. If you save a JPEG out at 99% quality, there is only a small loss of detail (a near perfect photo) but a large filesize. If you save a JPEG out at 80% quality (common on the web), there is much more detail lost, but the filesize will be smaller.

Most photos contain regions with great similarity and low levels of detail or pattern, and the JPEG format focuses compression on areas where there is little noticeable fine detail. For example, if you take two JPEGs of the same dimensions, but one JPEG is of a tree and mostly clear blue sky and the other is a of a crowded stadium with thousands of people, and you export them with the same quality level, then the photo of the tree and sky will have a much smaller file size than the photo of the crowded stadium, because there is little detail in the sky (hence large compression opportunity), but there is much detail in the stadium (hence small compression opportunity.)

You really notice the lossiness of the JPEG format if you place text over the photograph and export it at medium (80%) quality. You’ll get a smaller file size, but you will also see artifacting around the text. The text looks blurred and pixelated around the edges. This occurs because the JPEG compression algorithm combines adjacent pixels, so the pixels of the text combine with the pixels of the photo, and we get odd pixelated effects at the boundary of the text and the photo. PNG24 and PNG32 formats will not produce this pixelated effect around text, because they are lossless formats, but they will produce large file sizes.

There is a compromise available in Fireworks! If you need the smaller file size and ability to control the compression level of the JPEG format for photographs, but you also need to flatten text into the exported image and you want to avoid the pixelated boundaries around the text, then you can use the Selective JPEG option in Fireworks.:

(1) In the Optimize Panel, select JPEG then click on the pen and paper icon to the right of Selective Quality,

(2) a dialog for Selective JPEG Settings will open – check Enable Selective Quality; you can now choose the quality level and color for the overlay that will identify which area(s) of the image will be exported with a different level of compression, then press OK

(3) use the bitmap marquee tool to highlight the region of the image where the selective JPEG quality will be applied, then go to Modify > Selective JPEG > Save Selection as JPEG Mask

(4) a region the shape of the marquee will be filled with the Selective JPEG overlay color, and everything under that region will be exported with the Selective JPEG quality level

(5) if you want to flatten text into a photo and avoid the pixelated boundaries, you do not need to mask out the text area – simply go to Modify > Selective JPEG > Settings, then make certain that Enable Selective Quality is checked and also check Preserve Text Quality. Any text over the photograph will be exported at high-quality to avoid the pixelation, but the remainder of the photograph will be exported at the quality level specified in the Optimize Panel.

Hope this helps,

Dave

Glad you were able to get FW CS4 and get the CSS export workinG. The CSS and Images export feature was added as an extension to CS3 then improved and integrated in CS4 and further enhanced in FW CS5. The CSS and Images export demonstrated in this video was not available until FW CS4 – it was not available in Fireworks 8.

Have fun with your new FW CS4!

Also just realised Fireworks 8 will not export css to an external sytlesheet; even if the box is ticked. Styles are all inline.

Have tried closing program & even shutting down computer! No luck!

Is there any reason why text will not export using css layers / slices in Fireworks 8?

I have all images in slices & text areas not in slices. No over-laps.

When I export, the resulting html file contains the image layout only – no text. Everything else is perfect…there is just no text (and also no divs where the text should be).

Any help greatly appreciated!

Thanks

Sorry it wasn’t ready before you wrote this article!