Email Attachments changing to images on macOS Ventura.

All images and one-page PDFs get encoded with an "inline" directive. There is nothing you can do about it in Mail.

It doesn't matter if they are inline or not, you can add as many attachments as you email provider will send (size-wise).

You can ctrl-click on the image and choose Show as Icon, but that will not change the inline directive.

First you need to tell us which email app you are using. Second, have you checked with its Help information regarding adding attachments. For example, I use Thunderbird and the placement of the attachment makes that choice.