Nope, that’s not necessary. We have commissioned @ansimuz to do the graphics for us and for the community. I’ll repeat @sicher’s answer about the license of the newly released RTS pack:
"They are free to use as you wish. We encourage some attribution to the artist. Here’s the legalese from the terms:
5 . LICENCE TO THE DEFOLD ADDITIONAL MATERIALS
5.1 Subject to your compliance with the Defold Licence Terms, we grant you, for the duration of the legal protection of the intellectual property rights contained therein a non-exclusive, non-transferable, worldwide, royalty-free licence to:
copy and redistribute the Defold Game Templates, the Built-In Files and the Defold Materials as part of the Games only;
remix, adapt, modify, transform, make derivate works from and build upon the Defold Game Templates, the Built-In Files and the Defold Materials; and
make available copies of, and distribute, the Defold Game Templates, the Built-In Files and the Defold Materials as part of a Game to third party distributors who licence or sell such Games on your behalf, including without limitation app store providers such as Apple, Google and Amazon.
5.2 We shall retain all rights in the Defold Game Templates, the Built-In Files and the Defold Materials that we provide to you. Between you and us, you shall own all intellectual property rights in and to any modifications, derivative works or any software or material which you develop and/or build upon the Defold Game Templates or using the Built-In Files."