If we use <input type="file">, it will accept all file types. But it is possible to restrict the file types to only images, or certain image file extensions. To achieve this, we need to use the HTML accept attribute. This attribute is only used with <input type="file"> and serves as a filter to select file inputs from the file input dialog box.
Example for image select only validation,
<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
</head>
<body>
<input type="file" id="img" name="img" accept="image/*">
</body>
</html>