I had the need to have a file upload for images, so I added my little input type="file" field:

<input type="file">

I only wanted images to be allowed to be uploaded by the browser.

It’s a common thing, but I always forget how to do it.

Use the accept attribute and pass image/* to allow all images:

<input type="file" accept="image/*">

Or image/png to only accept PNG images:

<input type="file" accept="image/png">

The same syntax can be done to only accept videos:

<input type="file" accept="video/*">

or audio:

<input type="file" accept="audio/*">

Or a combination of them:

<input type="file" accept="image/*,audio/*,video/*">

Oh common thing - add multiple to allow uploading more than one:

<input type="file" multiple accept="image/*">

Of course this is only client-side validation, and you should also validate the mime type on the server when you receive the files.