Don't pirate (or buy) Photoshop
I hate Adobe just as much as the next guy (maybe a little more than the next guy), and I often get into conversations with other people who dislike their business practices. Often, these people will recommend "simply pirating their products", because clearly they do not deserve our money. This is all well and good, but you know what's even better? Not using Adobe products at all.
What do I mean by this? How is it "better" to not use their products? Let me explain. My perspective that of someone who really, really hates Adobe and wants them to disappear from this planet. I want to hurt them as much as possible, and I believe that not using their products will hurt Adobe more than pirating them. How so? Think about it like this: the only thing worse than being hated is being forgotten. Oblivion. Absolute obscurity.
When you use Adobe products, even if you haven't paid for them, you're letting them live in a little corner of your brain, free of rent. You'll carry that software choice around and unknowingly influence other people into using it. The more people use a product, the more people will know about it, and the more legitimacy it will gain. Some of those people will actually end up buying the products, statistically speaking. On the other hand, if no one ever used their products at all, none of this would happen. If you really hate something and you want to express your hate for it, you should refuse to even steal it. Just let it fall into oblivion and burn in the scalding fires of software hell.
If you absolutely must use Adobe for your job— you should still look for an alternative, but fine. If you're a hobbyist, just use Free Software alternatives like Inkscape, GIMP, or Krita. Please, do it for me.