Solved

PNG compared to JPEG and GIF

Posted on 2006-11-08
1
686 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
1 Comment
 
LVL 38

Accepted Solution

by:
lherrou earned 250 total points
Comment Utility
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

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

Uploading files to the web server has become common part of almost any kind of web application. People use different technologies to solve this, but regardless of the technology used, it is always useful to have some kind of progress indicator shown…
Foreword (July, 2015) Since I first wrote this article, years ago, a great many more people have begun using the internet.  They are coming online from every part of the globe, learning, reading, shopping and spending money at an ever-increasing ra…
Viewers will get an overview of the benefits and risks of using Bitcoin to accept payments. What Bitcoin is: Legality: Risks: Benefits: Which businesses are best suited?: Other things you should know: How to get started:
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

772 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

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now