there are probably lots of people who have already worked this out for themselves but if you don't want to spam your friends twitter/Facebook feeds or just want to get the screenshots in full 1920x1080 resolution then this is for you. Sadly there is no completely hassle free way to do this but it's not that painful once you've got setup.
I've never done a tutorial so if this is laid out badly or needs tweaking in some way to make it better let me know and I'll edit it.
You will need the Playstation App on your smartphone (oh and a smartphone!)
STEP 1:
Create an alternate PSN account. This is free and doesn't need PS Plus or anything like that. To do it on a PC just google "psn account sign up" and click the relevant playstation.com link for your region. Obviously remember the login details and screen name you choose!
STEP 2:
Log into your main account with the screenshots you want on the PS4 and send a friend request to your Alt account by searching for their screen name under friends

STEP 3:
Accept the friend request on the Alt account on your phone's PSN app or by logging in on the PS4
STEP 4:
Under your main account on the PS4 got to Friends, select the Alt account and send them a message

STEP 5:
Skip the text entry by pressing R2 and select the add attachment button (see pic) then select to add a screenshot and choose your desired shot (press options and change the sort if you want to see by most recent).

STEP 6:
Send the message on the PS4 and open the PSN app on your phone (logged in as the Alt account) and click messages on the top right. There is a refresh button on the top right of the messages screen if the message hasn't already arrived.

STEP 7:
Open the message on the phone and click on the button on the top right to save

STEP 8:
Use iCloud/Dropbox/USB cable to transfer to your PC or just look at it in your phone gallery and admire the high res

!!! BONUS quick tutorial - change the Share button to take a screen shot on a quick press for faster screenshots !!!
If you haven't changed your Share button options press it once to bring up the Share menu

Press options and choose Share Settings and change to Easy Share (the details of which are explained on the screen itself - see pic)

Sorry it's a bit rough but hopefully it will help at least a couple of people out! Let me know if you need any tweaks.
Cheers,
GM
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