Jpeg, Gif, Bmp etc.

[WILKO92]

Is there any reason why gif is the prefered format for images.

I have an assortment of gif's, jpeg's & bmp's and they all seem to work.

Graham

[jont]

GIF's are better for limited number flat colour files such as buttons

JPEGS are best suited to photo's

BMP's are best avoided as not all browsers handle them correctly

[I-CC]

gif and jpg's are images which are generally used throughout the internet along with more and more the png format.

bmp images tend to be larger in download size as people do it within windows paint which is limited in application, so no real 1st place and 2nd place, just which serves your need best, with gif having transparent abilities and colors (totals and removal of non used) abilities, with jpg having levels of compression to degrafation of quality..

No real reason, but plenty of options with differing ones which makes the choices...

[wjcampbe]

Its mostly down to file size and quality.

For detailed photographs, jpg are usually the best quality, but the downside is the files tend to be rather large. Using compression, you can trade between quality and file size and reach an acceptable compromise, but you still would not want many jpg files on the same page or it would be rather slow to load. The jpg format is best for the single 'more info' type detail image. However, repeated editing and saving of a jpg file results in quality loss due to compression, so this type of image needs to be created once and then left alone.

Gifs can give acceptable quality at a much smaller file size and also can be set to have a transparent background, so can fit into your design less obtrusively. Because of the smaller file size it is quite normal to have several gif files on one page and still have acceptable load times. Gifs can also be manipulated as required without excessive quality loss.

Bitmap or bmp is restricted to RGB colours, give poors results if scaled up or down in size, and usually cannot be compressed.
hth

[WILKO92]

So it seems I'm generally on the right track.

I have jpeg's for my section and product photo's, so I should get better definition and gif's for navigaton buttons.

I have some buttons in bmp which I shall now convert to gif.

Ta.

[Luddite]

We recently changed all our jpgs to gifs and it made a big difference to the speed of the site - abit laborious but well worth the effort.

[jont]

Yep - best to lose the BMP files and convert to GIF (or JPEG depending on the type) and then all browsers will be able to display your images properly.

As Bill suggests often best to play around with the amount of compression with JPEGS to trade off quality and file size - some image editors such as PhotoShop allow you to view 4 or more versions of the finished file at different compression values so you can check the file size and view the finished quality of the image side by side. Always best to work with the original JPEG and resample in one go rather than reduce, save, reduce and save due to the amount of information / quality lost during each JPEG save.