Blurry jpeg attachments in mail - OK when saved - what's wrong?

Question

Design

Designer, graphics,
web and tp teapot.
The problem is the jpeg file (export from the original psd 300 dpi, 2500x1000) the client in the attachment of the letter, opening it on the phone, sees it blurry. Me too, another person on the tablet - too - devices and OS are different. After saving, the file opens perfectly clearly.
It would not be a problem if the file was not important precisely from the point of opening as an attachment in a letter immediately clearly.
The question is - how do I save it or what is wrong?

Answer 1

Set dpi 72 for jpeg

Answer 2

When viewing attachments, the image can be adjusted to the size of anything: the screen, the application workspace, the viewport. When you attach an image of this width (2500 pixels) to an email, it is guaranteed to be reduced to a size that will fit on the screen (unless the recipient has a 4k monitor).
Therefore, to reduce the chance of resizing, insert an image at a resolution that is not excessive. For example - 1000 pixels wide.
However, it is impossible to guarantee the absence of fitting and interpolation (which cause blurring) of the attachment, because some mail clients, on the contrary, will stretch it when displaying it. You can try to insert an image into an HTML email, where the size will be specified in pixels, in the markup. But all this is already some kind of senseless perversions, it is not clear for what. Trying to impose on the user's device how to show attachments is stupid and pointless.

Answer 3

If possible, try the PNG format. Write if you try.

Answer 4

You just need to download and not worry about browsing the web. On Yandex in Google everything is fine.