Which Graphic Format is Best?

  Pesala 08:42 04 Mar 2003

I have always thought that JPG images were the most efficient for file compression, but it seems that this is not always the case. Someone on the Serif forum suggested that GIF images are usually better for screenshots.

I tested his theory, and was surprised at the results. You can check out and compare the screenshots from the links below (hopefully).

GIF 48K: click here\assets\images\FontThing.gif

JPG 48K: click here\assets\images\FontThing.jpg

PNG 25K: click here\assets\images\FontThing.png

By the way, The Font Thing is an excellent freeware font manager available from: click here

  Hachi-Roku 08:59 04 Mar 2003

well i find gif to be at less quality and take up more space! i always go for jpeg myself! guess this is my view on it!

  Pesala 09:29 04 Mar 2003

Just click on the links and see for yourself. I had to reduce the quality of the JPG to 35% to get the same file size as the compressed GIF, and the loss of clarity is very obvious. The PNG is even smaller but just as good as the GIF.

  €dstow 09:41 04 Mar 2003

The "best" graphics format depends to a large extent on what you are using the graphics for. There are compressed formats (JPEG is one of those) and uncompressed (eg TIFF). For my work, a compressed format approaches the totally useless as, during compression, information is necessarily lost, never to be retrieved. Each copy of a compressed image results in more loss and more deterioration. This doesn't happen with an uncompressed format and however many times it is copied, it remains the same. The downside of an uncompressed format is its very large size.

So, swings and roundabouts!


  Pesala 09:48 04 Mar 2003

I know that JPG is lossy compression. What about GIF and PNG, are they lossy or lossless?

Tiff files can also be compressed to varying degrees, can't they?

  Goldcroft 09:53 04 Mar 2003

Is it just my setup Pesala, but all three of your clicks produces a virtually unreadable image, very poor in quality.

€dstow is a graphics pro, but for my work, including pics for websites, newspapers etc I have always used jpegs.

Beware anyone downloading The Font Thing without looking properly - it's not compatible with XP.

  Pesala 09:59 04 Mar 2003

I just tested it in IE. What is does is zoom the images to fit the page, that is why they are all blurred. Hover your mouse over the bottom right corner and click the icon that appears to resize the image to 100%.

Better still, use Opera and zoom to any percentage you wish.

  Pesala 11:52 04 Mar 2003

Internet Explorer Options, Advanced Tab, Multimedia, uncheck Enable Automatic Image Resizing

  Aspman 12:24 04 Mar 2003

Rule of thumb for web graphics.

If it involves large blocks of solid colour, or relatively few colours (icons, logos) use a gif.

If it involves gradients of colour shading (people, landscapes) etc use a jpg.

Don't open a jpg edit it and resave as you will get a gradual reduction in quality (coz its lossy) bit like photocopying a photocopy over and over.

For jpgs you always need to try to work from an uncompressed original if you can.

  Pesala 12:48 04 Mar 2003

Any comments Aspman on JPG compression ratios?

Irfan View, for exmaple, has an option to reduce the quality setting between 1 and 100 (highest quality, least compression).

What setting do you normally use? Or do you not bother, and just use the default for your favoured program?

Have you ever used JPG2 or PNG formats?

  Aspman 13:26 04 Mar 2003

I'm a photoshop user, and to be honest I have to play around with the settings to get the best results. I find you get away with higher levels of compression and lower qualities in smaller images. Also if you have an image that has a lot of straight lines jpg compression tends to look worse something to so with the way the compression works.

In photoshop I tend to stick the with a couple of the predefined levels medium and high they roughly equate to 30 and 60

I've never used Jpg2 and I don't think it is a well supported format yet. PNG I've tried to use but I find it hard to get a images with a small enough filesize for 56k users.

IMHO just learning when to choose between gif and jpg will get you out of most problems. If you need to put in a high quality image (say of a product or place) put in a thumbnail first and warn users that the full image is quite big and will take a bit to download. If you warn them first they don't get so annoyed.

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