Some of the images I’m using on post’s featured images are showing some quite nasty compression artefacts even with “Crop Featured Images” activated. Using the Lightroom feature shows that the uncompressed image is there on the server, as you would expect.
Here’s a good example of the problem.
Is there anyway around this? It’s making the articles look cheap, quite the opposite of the theme’s design!
All the best
Francis
Default compression for images is managed by wordpress unless you’re using a plugin of some kind; not the theme; the default “quality factor” is 90 but can be increased to 95 or 100 (no compression) by adding line in functions.php to set that. But not recommended. We typically change our compression level to 60, for faster page speed.
Be aware that jpeg images with a lot of “reds” don’t compress well ever, sadly to do how lossy jpeg/mpeg compression works.
Also, if you upload an image with very low quality the quality only gets worse.
For charts such as you’re using on your sample page, it’s best to use PNG files vs jpeg and embed those directly into the page so they are not resized/resampled to new sizes except for thumbnails. Try saving it as PNG file and place in the post, and you’ll see a HUGE improvement.
Nothing with reds/orange/dark pink compress well with jpeg — it’s nothing to do with the theme 🙂
Hi Christopher
Thanks so much for this. Curious about the Jpeg compression. Guess it’s one of those things you’ll only know when you need to! I find it really stands out with whites (as the pages’ backgrounds are a really uniform white) and whenever blocks of colours are used in (say, logos).
We normally only use one image per post and feature all our posts on the front page so embedding won’t be suitable for the majority of the time. Will try with PNGs and see how we get on.
Thanks again!
