Usually when I post images here I resize them to 800x600 then save them as JPEGs.
But I've decided to start using WebP instead. This is a more modern image format developed by Google and recognised by nearly all browsers and devices.
To test this, I saved the following two images from the same (larger) JPEG. No tweaking contrast or sharpening, I just resized them.
(https://bikediary.uk/images/250723bike.webp)
(https://i.ibb.co/NgGPW1nD/250723bike.jpg)
The first is the WebP, the second the JPEG.
I saved the JPEG at 92 quality, the WebP at 86 which is supposed to be equivalent.
It's hard to tell without zooming in so I did, and it turns out that when you pixel-peep, the WebP does look a bit better than the JPEG. But it's only 65% of the file size. Less storage consumed, less bandwidth when your browser gets it from the server and it should load a bit quicker as well.
In this post I've published an image in a third format (AVIF). This is even more space efficient than WebP. But for esoteric technical reasons you may not be able to see it. For me it works OK in Firefox, but not Chrome or Chromium, which are stricter about the file type.
Pity because it looks as good as the JPEG or the WebP, but it's only half the size of the JPEG. So I'll stick to WebP.
Oh .. just noticed that Chromium and Chrome don't show the WebP either!
(https://bikediary.uk/images/250723bike.avif)
OK all three images posted above should work in all browsers now. I've set up the image hosting site to use HTTPS as well, which was the problem - some browsers don't like mixed protocols on the same page for more modern image formats.
So I can use AVIF format for images - less than half the size of the JPEG for slightly better quality, that's a result.
If interested, these are the respective file sizes:
JPEG: 244K
WebP: 144K
AVIF: 96K
So on a modern browser, the AVIF will load more quickly as well as being less resource-expensive to store - on the image host, and in your browser cache. These are small test images of course; the difference will be more significant for images of greater resolution.
Here's the catch, though - some image hosts (ImgBB for example) won't accept AVIF. Or in some cases they will but they'll convert it to a JPEG, which will incur a loss of quality from re-encoding as well as nullifying the efficiency benefit.
But generally, WebP is definitely a better bet than JPEG. I'll be posting AVIFs on my bike pic image site, and WebP on ImgBB.
I cropped and zoomed a region of the image for all three formats, as follows, into a lossless format (PNG) and combined them into a single image, for comparison:
(https://i.ibb.co/chWtczLc/compare-strip.png)
Easy to do with a command line tool.
Then I got ChatGPT to analyse the image:
(https://i.ibb.co/H0VHGL8/gptopinion.png)
I tend to agree with the assessment, however I do see more colour saturation in the middle image.
I find this interesting, is this a form of compensation?
I think, at our age, none of them are optimal ;D
Quote from: Thenop on July 24, 2025, 08:46:28 PMI tend to agree with the assessment, however I do see more colour saturation in the middle image.
I find this interesting, is this a form of compensation?
I can't honestly really see a meaningful difference in quality between any of them. They do look a bit different, because they use different compression methods.
Back in the early '90s when I worked with Sun workstations, viewing images on a computer was a real novelty. It was something you couldn't do on an IBM PC or clone, back then.
The predominant image format was GIF, which was considerably less efficient than JPEG and reduced images to 256 colours (in practice not that bad for simple snaps). The hardware was dramatically slower back then (despite being exquisitely expensive) and there was no GPU acceleration. An image viewer could take a few seconds just to make an image appear on your screen.
GIF is still in use today for animated images, something JPEGs don't do, and it can still be used for static images.
Here's a GIF of the same image as the other three. It's the biggest of all of them, though only 272K. Thought it would be bigger than that.
But look at the sky - the reduced colour palette causes steppy transitions between the shades of colour in the clouds.
(https://i.ibb.co/Vcv7PB0h/250723bike.gif)
I am aware of the limitations you mention, and surely GIF, as a near antiquated has served its purpose. Clearly the image suffers tremendously fomr the compression.
What I am seeing though, and maybe my mind plays tricks on me, is a bit more colour in the middle of the three images. Look at the pink-ish flowers seen through the fence in the middle, of the green of the grass for that matter. It is not as clean as the other two images, I am just seeing more, and perhaps more saturated colours.