Welcome, @gerglisofi17. You have a smart friend. LMAC is a good place to network and meet new people. Thank you for designating LMAC as 20% beneficiary. This is one of the requirements if you want a community upvote and want to be considered for a prize.
Now let's get to your collage. Lovely! It is October, and you have let your imagination carry you to a seasonal theme. The colors are great and the fantasy aspect is also effective. Your friend is correct. Using copyright-free images is essential here, and Pixabay is a good source. Another great source is our own image library. I don't know if your friend told you we are building a library (#LIL) of copyright-free images. If you use images from our library, you get stronger support (bigger upvote) from the community. Here's a link to the library for the next time you make a collage.
The news gets even better. You can contribute photos to the library and also get support from the community for doing that. Here's a link to a post describing how to contribute your own (taken by you) photos to LIL.
If you have any questions, drop in at our Discord channel and ask. We are friendly :)
Again, welcome. You will have fun. I do, all the time.