is it allow to change licenses plate ?
it is allowed
What you may do to a photo:
Crop and/or resize an image.
Adjust the level or curve values.
Alter the colour tone of the image (gradient maps, photo filters, colour balance, etc).
Car body colour change (all stickers/design features must remain, see "Remove Items" rule).
Adjust brightness, contrast, exposure, shadow/highlights.
Enhance shadows or highlights (dodge and burn tools in Photoshop, for example).
Add noise and/or diffuse glow.
Add a post-game tilt-shift blur, or apply a motion blur to a stationary Photomode shot.
Make use of Layer Blend Modes.
Use a Sharpening filter and/or tool.
Scale or enlarge rims.
Remove or modify license plates.
Remove the GT watermark.
Add a personal signature.
Clean up or fix jaggies, texture pixelation, or colour separation.
Add a vignette effect.
