Minor GIF corruption

[jxm28788]

I've noticed this a few times with some of my gif images -

when I look at them in a graphics program they look perfect, but when I look at them on my site they don't look quite right. The problem is usually white dots appearing around the edges of text or in the middle of pictures.

The gif size that is specified in the html is the correct size, so what gives? why aren't the GIF displayed identically?

[NormanRouxel]

The could be GIF's with transparency (usually set to the white background). However you may have some cells that are not quite pure white so the transparency didn't get applied to them and they show.

Norman

[jxm28788]

hmmm, that's a possbility. when I zoom in on the text in ms paint the edges are blended (anti alaised???) so there is like a grey scale areound the edges between the black background and white text.

It's feasible that one of these shades could be the 'transparent colour'... But how to I fix it...?

[NormanRouxel]

Look at these images in an image editing program that has the capability to display the background transparancy. E.g. Paint Shop Pro shows it as a grey checkerboard. This will let you see what's transparent and what isn't.

Re fixing this. It's probably hard work to fix those few stray pixels - all you can do is either make them transparent one by one or set them to the expected page background. There won't be any easy way to automate this.

When creating new gifs you can do this: When making such images is to use a background colour that is close to the expected page background. When you add text, any anti-aliasing will create intermediate cells close to that colour. Now set the background colour to be the transparent one and you while you'll still have some cells that are the "wrong" colour they will, at least be close to your page's background.

Norman