Expiring Today—Celebrate National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

PNG compared to JPEG and GIF

Posted on 2006-11-08
1
Medium Priority
?
768 Views
Last Modified: 2013-12-25
I've used GIF and JPEG for ages now, and begin to discover PNG. I hear from many people it's better, and I know that transparancy is better in PNG - if supported by the browser of course.

Normally I use JPEG for photo's. If I use PNG (24 bits), the image size is much bigger, and I cannot specify a compression rate (using Photoshop 6). As an example I took a photo of 800 x 600 pixels. Saved as PNG it was 800kb, and the JPEG version varied between 100kb (for high quality or 60%) and 500kb (100% quality). So the best JPEG quality is half the size of the PNG. Why is PNG better?

If I save to PNG (version 1), then reopen the saved PNG (800 kb big), save that again as PNG (version 2), the size grows to 950kb. If I reopen the last PNG (v2) and save it again as PNG (version 3), it seems to keep the last size. Is this always the case? Is PNG 24-bits lossless? Or at least not incremental on losing information?

What do you prefer? JPEG or PNG?

How about GIF? I think I won't use it anymore. I've noticed PNG-8 has comparable file sizes. I never use animated GIFs, so I don't need that (and don't know if PNG supports animation). Do you have reasons to prefer GIF over PNG?
0
Comment
Question by:grexx
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 38

Accepted Solution

by:
lherrou earned 1000 total points
ID: 17898617
Grexx,

First of all, remember that PNG was intended as a replacement for the GIF file format when Unisys said they would enforce the LZW compression patent, which was used in GIF. JPEG is still the primary lossy compression method for photographic or photographic-style images. PNG is not going to be the smallest format for photographic-type images in most cases. On the other hand, for a simple image, the GIF format, while called loss-less, in fact discards color information to achieve some of it's compression, and is limited to 256 colors or less (as set by user/software). PNG often, but not always, outperforms GIF on image quality and compression in images of these types.

The following article shows some excellent comparisons, and discusses when each should be used:
http://www.websitetemplatedesign.com/oscommerce_tutorials/printer_136.shtml

Cheers,
LHerrou
0

Featured Post

Plesk WordPress Toolkit

Plesk's WordPress Toolkit allows server administrators, resellers and customers to manage their WordPress instances, enabling a variety of development workflows for WordPress admins of all skill levels, from beginners to pros.

See why 2/3 of Plesk servers use it.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When it comes to write a Context Sensitive Help (an online help that is obtained from a specific point in state of software to provide help with that state) ,  first we need to make the file that contains all topics, which are given exclusive IDs. …
When crafting your “Why Us” page, there are a plethora of pitfalls to avoid. Follow these five tips, and you’ll be well on your way to creating an effective page.
This tutorial walks through the best practices in adding a local business to Google Maps including how to properly search for duplicates, marker placement, and inputing business details. Login to your Google Account, then search for "Google Mapmaker…
The viewer will get a basic understanding of what section 508 compliance can entail, learn about skip navigation links, alt text, transcripts, and font size controls.
Suggested Courses

719 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question