I would just use string split here:

var url = "www.test.com/is/images/383773?wid=200&hei=200";
var output = url.split("?")[0] + "?@HT_dtImage";
console.log(output);

If you only want to target query strings havings both keys wid and hei, then use a regex approach:

var url = "www.test.com/is/images/383773?wid=200&hei=200";
var output = url.replace(/(.*)\?(?=.*\bwid=\d+)(?=.*\bhei=\d+).*/, "$1?@HT_dtImage");
console.log(output);

You can match either wid= or hei= until the next optional ampersand and then remove those matches, and then append @HT_dtImage to the result.

\b(?:wid|hei)=[^&]*&?

The pattern matches:

• \b A word boundary to prevent a partial word match
• (?:wid|hei)= Non capture group, match either wid or hei followed by =
• [^&]*&? Match 0+ times a char other than &, and then match an optional &

See a regex demo.

let url = "www.test.com/is/images/383773?wid=200&hei=200"
url = url.replace(/\b(?:wid|hei)=[^&]*&?/g, "") + "@HT_dtImage";
console.log(url)

You can make use of lookaround using regex /\?.*/

const url = 'www.test.com/is/images/383773?wid=200&hei=200';

const result = url.replace(/\?.*/, '?@HT_dtImage');
console.log(result);