Not by default.
The phones come from the factory with the feature disabled. If you use the provisioning template from 3CX (which you do if you specify the model when installing) it will enable the feature and then download the 3CX logo. This is what you are seeing.
I usually install a custom logo which represents the clients brand. The Yealink website has the tools (free and instructions) that allow you to take a BMP file and convert to a DOB file which is then uploaded into the phone. The T22 has 3 options with regard to the logo - none, system or custom. OPen the phone web browser and navigate to phone and then the sub-tab features. You will see an entry that says "use logo", where you can make your selection.
If you select none, then only the standard phone display will show. no logo and no alternating display. If you select system, then the Yealink logo will display. If custom, it will display the logo file called for in the provisioning template or whatever you manually upload via the web browser.
However, keep in mind my earlier caution - if provisioning is enabled, it will overwrite any manual settings made when the next provisioning cycle takes place. You will need to modify the template so you get what you want when provisioned or you will need to disable the provisioning/update settings in the phone so that provisioning does not occur. I use both scenarios as it depends on the level of complexity needed by the particular phone. I leave some provisioned and modify the templates and with others I disable the provisioning and manually setup.
I almost always use a custom logo. It is especially useful when selling a system to go in with a phone with a large (color) display showing the prospective customer's logo as most don't even have a clue that something like that is possible. While the color display shows it off more, the feature is available in most of the other phones (such as the T22) as long as they have a graphical display.
Of course, some logos will look better than others as it depends on size, intricacy, resolution, etc. Nevertheless, it is generally called "branding" where the phone display is being used a promotional tool. 3CX is doing precisely this by using "your" display to promote their product. People who have no idea of who or what a 3CX is might see this on a display and ask. You must admit that the users of the system have no idea of the PBX maker and if asked and not using MyPhone, would likely be inclined to look at the phone and see its manufacturer's name and guess that the PBX is the same as the phone make.
I have attorneys (vain by nature) who love it. They put a T38 or T32 (color) in all common areas where clients and particularly other outside attorneys are apt to see and use. It is a statement of their success...like driving a fancy car..... regardless that they may still be a start-up.
Not only does it help me sell, but to a degree it promotes their name and sales.....and I get a better margin on the sales. Even if not color, most still consider it cool and impressive and more importantly desirable. Would you rather have Cisco, Polycom, Yealink, Panasonic or some other phone manufacturer's name/logo on your display........ or yours?