If you feel the urge to use Partiko on the PC, there is a way.
Using Bluestack or any other Android emulator you can use all your phone apps on PC.

Search for Bluestack in your webbrowser, download and install.

(While not necessary, it's recommended you switch on "Virtualization" for your CPU. You can do that in most systems by going into the BIOS and search for it under "advanced features" or similar. Every motherboard has it's own BIOS so the nomenclature will differ and some boards/cpu's might not support it, thought I think most do.
Getting into the BIOS is usually done by restarting your PC and holding down the "delete" key once the PC starts booting up again.)

Bluestacks is an emulator like I said.
It's gonna run Android on your PC and once you connect your account to it, you can start posting from your PC.

There are some quirks though. Posting images is a bit hindered. You'll have to somehow get pictures into the Gallery app and then let Partiko get the pictures. It's 100% like on your phone, you can forget about everything PC related basically. (except using mouse and keyboard for navigation)

Is it a preferred way over simply posting on Steemit?

No. I still find Steemit's posting better and more powerful, but it does take some typing and memorizing of different codes. On Partiko it's a bit easier, but it has less functions.

But it's way more convenient typing with a keyboard and having a big screen.

I can imagine diehard phone-gamers would enjoy this method as it will show their games on a big screen and run them 100x quicker... let's face it, phone hardware is no match for old PCs, let alone new ones.

If Steemit and other clients are more convenient for PC, why use Android emulation in the first place?

Because I want to earn Partiko Points :D

Is there a way to add images from my PC?

Post you post without any fancy editing and pictures using Partiko.
Then, because you are behind the computer, use Steemit (or any other site) to edit your post.
You'll get the benefits of posting using Partiko and making your post more beautiful. That is if you think it's necessary :P

So...

What apps and sites are you using to interact with the Steem-blockchain?

Posted using Partiko Android