Yes, most online
high quality image converter tools are safe to use if you choose a trusted website. Before uploading your images, check whether the tool uses secure HTTPS encryption and has a clear privacy policy. If you're working with personal or sensitive photos, it's best to use a converter that automatically deletes uploaded files after processing.
A reliable high quality image converter should also preserve your image quality while converting it to the format you need, without adding watermarks or unnecessary compression.