Oh most of us that change it so often make the アイコン ourselves.
If あなた ever find an image あなた want to be an アイコン I could always make it for you. XD Ive made probably near a thousand または so アイコン によって now. I really enjoy making them
But essentially あなた 検索 up whatever あなた want an アイコン of, あなた find an image that あなた think would make a good icon, take it to some kind of editting software (or paint if あなた dont plan to do much to it), and at the very least, crop the image to be the size あなた need it to be (square)
あなた can get もっと見る creative with it the もっと見る your practice too
I usually used
link to 編集 and crop and all cause its like Photoshop but online free and has no downloads. Not as good as Photoshop but definitely plenty enough.