You can read more about Medibang from this forum thread: The best part is that it is totally free. It also allows you to save your work on cloud to work from different platforms be it Android, Mac or PC, depending on what you've already got so it won't force you to purchase anything else. I recently made a transition to Medibang Paint which has a very easy learning curve, is light on system resources(even works on my dinosaur of a PC) and also allows me to create beautiful artwork still using a mouse. When I started I only had MS-Paint to work with and still created good pieces even while drawing with just a mouse. Art is like an exploration and there is no one fixed route to get to the destination or discovery of what you can create. It's entirely up to you and how you feel.

If you're just starting out though and/or budget is an issue, I'd probably recommend starting with something like Krita to learn on and decide if you even enjoy digital art before shelling out for the pricier software like Photoshop or Corel. Also, it's not uncommon for an artist to work in more than one of them I use both Corel Painter and Photoshop CS6 along with other Inkscape for vector art and learning Blender for digital 3D. Other good options for digital art software are Procreate, Clip Studio Paint, Art Rage, and Krita, but there are loads more.

If doing it primarily for you own enjoyment than it doesn't matter so much which program and there are many options out there, some even for free. Corel Painter is another excellent professional level painting program and a close rival to Photoshop. If professionally, while there are other very good professional software out there, Photoshop is still the industry standard across the board on 2D digital art, whether matte painting, digital painting, photobashing/photomanipulation, etc. Are you planning on doing digital art professionally or just for a bit of fun? Also, what type of digital art? Photomanipulation, digital painting, both? Some programs are better at one type of digital art than another. It all depends on what your needs are as an artist.

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