The easiest way to add a bit of personal flair to your device is to add a custom wallpaper. With these new high resolution displays on devices like the HTC One it can be hard to find an image with the clarity you need. XDA member "Neilmc1983" has compiled a collection of 550 1080p wallpapers that work perfectly on the HTC One. The wallpapers come in a zip. Just download file, unzip it, then you can choose your wallpaper by long pressing the photo you like and setting it as your background. Grab the zip from the source link below.
Via XDA
Via XDA