Jpeg colour doesn't match website background

[Mark-the-Wizard]

I currently have jpeg images that fade out to match a blue background of a web page. The colour isn't quite matching so there is a faint edge all around the image. It works fine as a PNG (but way bigger) can anyone help what may be going wrong? I've tried saving with and without embedded color profiles and have the doc set as sRGB. Thanks in advance.

[D Fosse]

Always embed the profile. No exception. It's the only way to define the color.

If it's one or two numbers off, it's probably the jpeg compression. The jpeg algorithm compresses the color component more aggressively than the luminance component.

Edit: I see it matches as PNG. So yes, it's the compression.

[Mark-the-Wizard]

Thanks for the input. Is there away to counter this or is it a case of manually tweaking the colour to hopefully get a match

[D Fosse]

I think the compression squeezes the color into slots. So if you try to tweak, it only gets worse.

I'd use PNG. One single image can't impact load times all that much.

...or perhaps change the background?

[Mark-the-Wizard]

Thanks again, I may end up tweaking the background. I've 3 images it's happening on - the optimised jpegs are 100-150kb each, PNG is nearer 1mb each