I've just now independently run into this same multiple-size screenshot issue, and I'm going to give this a go. The first problem I ran into was finding legit iphone background screenshots, but I think I've solved it by specifying the size in Google's image search (click on Tools, then Size, then exactly 1242x2688 or whatever screen size you need):I usually download both pictures without background from Google then added the screenshoot of our App(iPhone5) using photoshop.
Did you get a B4I app running in that simulator? My plan is to unzip the .IPA out of the hosted-builder Archive.zip, then unzip that, then rezip the .APP tree to a .APP file, then try uploading that to the website. But I'm too tired right now to do it without making mistakes.The first option in that link looks good - looks like a web based simulator ... I shall investigate it more.
Thank you, JackKirk, it seems it is really useful, as you can choose your own devices to test (there are many available, with different OS versions, for both iOS and Android).For anyone who is interested, I may have found another possibly bettter solution - well it worked for me any rate and is more in the spirit of what the Apple meisters are after - i.e. proof that the app works correctly on all iPhone models.
I discovered AWS Device Farm: https://aws.amazon.com/device-farm/
The only real hassle is setting up an AWS account if you don't have one.
Cost is USD0.17 / minute - about USD10 / hr - BUT you get the first 1000 mins (16 hours) FREE
It is incredibly easy to use - you could even do realistic app testing - e.g. you get complaints about your app not working on a specific device that you naturally don't have.
For iOS you just take the ipa out of ...\Objects\Archive.zip and paste it onto the device web page - 20 secs later you are running.
Images are quite small but a bit of Paint.Net fixes that.
It is not confined to iPhones - has heaps of Android devices also - so testing/troubleshooting on obscure devices becomes realistic.
For image manipulation I thoroughly recommend the free Paint.net app - in functionality somewhere between the old Windows Paint applet and Photoshop:UPDATE: I tried a remote connection and found out that you can later download the video and use VLC at 100% size to capture the pictures. It created me a 720x1558px "screen shot" for an iPhone XS Max (6.5" screen). Apple requires a size of 1242x2688px (portrait). I also spent 2 minutes of my free quota on it to get basic screen shots. Not bad.
As you have found, you have to use the "Remote Access" tab to get screen shots directly.But unfortunately I could not get any screen shots, only the video. It says 'No screenshots found'.