PNG 8 or 24?

[Peter S]

Since seeing the discussion on "Save for web" in Photoshop I have been experimenting and found I can choose to save PNGs as PNG-8 or PNG-24. PNG-8 seems to produce very jagged outlines and I assume that when using the normal Save as function in Photoshop it chooses 24 automatically.

The PNG-8 files are about half the size of the PNG-24 but I can't see much use for them with the quality I seem to be getting.

I would be interested to know if anyone can suggest the best setting in Save for Web for PNGs.

Peter

[Igor]

Peter,

Save to PNG24, because before creating of EXE file PicturesToExe 5 automatically converts all PNG/GIF to internal 24 bit or 32 bit format - BMP compressed to ZIP. It gives same file size as PNG24, but image loads in 2 times faster than PNG.

[dpearcePNG]

The correct understanding of this answer is very important to me because I am about to embark on the most complicated P2E presentation I've ever done.

I can understand the advantage PNG24 gives quality wise over PNG8, but I am confused about the comment concerning 24-bit BMP. Are you saying 24-bit BMP loads twice as fast as PNG24?

Dave

[Igor]

Dave,

We don't include PNG images to created EXE file of a slide show.

Instead this, we decompress PNG image to BMP image and compress this file to ZIP archive. This ZIP file will be embedded to EXE file of your slide show. No losses in quality. But such converted images load faster in slide show. File size also very small, like PNG.

[dpearcePNG]

So for images that do not require transparency, using BMP for the slides is an advantage?

Dave

[bmccammon]

I recommend that you NOT use BMP files as your source files for the show. Why not use JPG, cropped to 1024x768 with a compression level of about 7-8? That produces high quality images, small file sizes and works well in PTE. Good luck with your show.

[ksf]

With all due respect, if you find a particular setting for saving PNGs doesn't give the quality you require then the answer surely is to use the setting that suits your purposes the best? As Bruce has said, JPGs work well for the main images but as for PNGs - at the end of the day, only you can be the judge of what quality you want in your finished sequence.

[dpearcePNG]

I didn't mean to turn this into a "what format is the best" conversation.

What I am interested in is this comment from admin1:

"But such converted images load faster in slide show."

What format is the "such" format? I'm interested in making such I'm not making P2E work harder to produce a fine presentation than it has to.

Dave

[bmccammon]

I would venture to guess that the vast majority of PTE users rely on JPG files for their shows unless there is some special purpose or need (eg, transparency). I have to believe that if there was a better format that reduced loading in PTE and produced a better, smoother, more reliable show then we'd all be using a different format. If I'm incorrect I'd sure like to learn the "better way".

Best regards,

Bruce

[JPD]

But such converted images load faster in slide show.

That mean that the internal compressed and lossless format is quicker to decompressed than PNG (Just a little more than JPG).

If you use BMP without compress it, the file will be heavier but there will be no time for decompression.