Try something like
<input type="file" name="my-image" id="image" accept="image/gif, image/jpeg, image/png" />
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Live demo here
To select only image files, you can use this accept="image/*"
<input type="file" name="my-image" id="image" accept="image/*" />
Live demo here
Only gif, jpg and png will be shown, screen grab from Chrome version 44