Images on posts blurry

Those images aren’t blurry as such. They are just smaller then their image size, so things like text will always appear to be not quite as clear because you’re compressing the image size so browsers need to interpolate that and decide how to compress the larger image into a smaller space. That’s why they look better for you when you zoom in.

The ideal way around this is to display the images at 100% size so that they don’t have to scale. Either that, or set it up so that the images can open up a lightbox or link to the full-sized images so users can see then at full size.

@catacaustic is spot on. Responsive image resizing will effect the image size. Which is a good thing.
The image can be enlarged by the user as required. The WordPress Core image block has an expand on click feature built in as of “WordPress 6.4”
As an additional side note. I notice your images are predominantly .png in format. This image format is great for the type of image displayed on the page indicated. PNG 8 with a colour map of eight colours will greatly reduce the image size. (unless you need transparency. There are also a number of image optimisation plugins available which can help.

@catacaustic but i still don’t understand why on my smaller laptop screen (resolution 2560x 1600) the images are fine, no zoom required, but on my PC my much bigger monitor screen (1920×1080) I have to zoom in.

You said it in your own post… It’s all to do with screen resolution and display quality.

On a laptop at 2560 a pixel is tiny. Difficult to see where one meets the other. That’s why retina screens looks o good – tiny pixels that “trick our eyes into not seeing them.

On a desktop at 1920 pixels are larger. Depending on your screen size then can be massive. These don’t blur together anywhere near as well for human eyesight. Hence, they will never look as crisp.

This all has got nothing to do with your images, the website or WordPress. It’s 100% to do with the hardware that you’re using to display the site.

If thats the case I guess I’m kind of glad there’s nothing I have to fix on the website. Though it’s still quite annoying that It’s blurry, but oh well I guess.