Upload image without going through Jetpack

The image upload process is entirely controlled by WordPress, and by image optimization plugins you may use on your site. Jetpack doesn’t touch your images as they are being uploaded to your site.

That said, Jetpack does come into play later, when the images are being displayed on your site, and if you use Jetpack’s Photon service. The Photon service only applies lossless image compression by default, but you may have found a bug on your site, maybe via a custom color profile or a custom image format that Photon doesn’t manage properly yet.

Could you go to Jetpack > Settings > Appearance in your dashboard, and deactivate the Photon module? If the single images displayed on your site then start looking better, we’ll know the problem is caused by Photon. Could you then give me a few examples of the images that are dazzled so I can take a closer look and see what we could do to fix things?

If, however, the images don’t look better when you deactivate Jetpack’s Photon module, it means the problem isn’t caused by Jetpack. I would then recommend that you deactivate all other plugins that may interact with your images on upload. If that doesn’t help, you’ll need to investigate further, with different image types and by maybe contacting your hosting provider to ask them about the image processing library currently available on your server.

Let me know how it goes!

on the page I’m creating (landing page), the images are shown as the Jetpack URL

That will indeed happen as long as the Photon module is active under Jetpack > Settings in your dashboard. When the module is active, each one of the images displayed in your posts and pages goes through the Photon service as soon as it is loaded on the page.

this leaves the images with poor quality. See below:

Uncompressed image: http://idiomas.proddigital.com.br/wp-content/uploads/sites/4/capa-guia-landing_page.png

Image on your server: https://i2.wp.com/idiomas.proddigital.com.br/wp-content/uploads/sites/4/capa-guia-landing_page.png?w=640

Notice that the image on your server loses its quality.

Photon maintains 89% of the original image quality; we’ve opted for that default setting as it applies a compression that is not visible. Bringing the quality downer starts making visible changes to the images’ quality.

I can indeed notice a loss in quality with that image, though. I believe it’s most likely linked to the image format, that makes compressing without losing quality a bit more difficult. That said, you can use a code snippet to overwrite the default quality settings of Photon and force it to maintain a quality similar to the original:

add_filter('jetpack_photon_pre_args', 'jetpackme_custom_photon_compression' );
function jetpackme_custom_photon_compression( $args ) {
    $args['quality'] = 100;
    return $args;
}

You can paste in your theme’s functions.php file, or in a functionality plugin like this one.

I hope this helps!

Since you’re adding the 100% quality parameter, you’re indeed removing all compression from Photon. Loading the same image without that parameter would yield different results, for example:

https://i2.wp.com/proddigital.com.br/wp-content/uploads/sites/4/Estudando-Ingl%C3%AAs-Online.jpg -> 22.6kb

I’m not sure that parameter is really needed, in fact. I personally don’t see any difference in quality between those 2 images:
http://proddigital.com.br/wp-content/uploads/sites/4/Estudando-Ingl%C3%AAs-Online.jpg
https://i2.wp.com/proddigital.com.br/wp-content/uploads/sites/4/Estudando-Ingl%C3%AAs-Online.jpg

I see what you mean. I’ll ask one of our Photon experts to take a look, and I’ll get back to you as soon as I have some news!