Yes, you can create an album and not upload any images to it yet. User Tools > Create/Order My Albums > New Album. (
Here's a guide I wrote, if anyone needs it.)
I don't see anything wrong with uploading the same image, at different sizes. But there are a couple of issues with SVGs. One is there's a problem with the thumbnail display. (Somehow it becomes cropped. I'm hoping someone with the right skills will be able to fix the plugin
http://forum.inkscapecommunity.com/index.php?topic=79.0.) And also, clicking directly on the thumbnail does not display the image. You have to click in the white space to the left or to the right of the thumbnail.
There is not a preferred size for any image, as far I'm concerned. That is up to the artist, what size are their images.
In considering what size to make my own images, if I want them to be fully displayed on the screen, I like to limit the height between 600 and 700 pixels, and width between 800 and 1200. I guess most computer screens fall somewhere within those limits, so most people will be able to see the whole image, no matter what kind of screen they have. However, with the advent and popularity of tablets these days, which seem to have generally smaller screens, it might be something to consider.
Yes, you can use the URL that the gallery creates, to embed the images elsewhere. How to retrieve that URL can be a bit tricky.
If you'd like the actual gallery page to open, so that all the file info is available (the intermediate image), when someone clicks your link, here's how to get the right URL. Open the intermediate page of the image (the page with all the file info). (You may need to click the Hide/Display File Information button to display the info.) Look through the file info, and copy the text to the right of "URL:".
But if you want only the image itself to be displayed, without the gallery, here's how to retrieve the proper URL (if anyone can't figure it out):
For PNGs, you must have the full size image opened.
a) In Firefox, right-click on the full size image > Copy Image Location
b) In IE, right-click on the full size image > Properties, then copy the Address (URL).
You'll know you copied the correct address if it ends in .png.
For SVGs, you can get the proper info from thumbs, intermediate, or full size image.
a) In Firefox, right-click > This Frame > View Frame Info, then copy the Address.
b) In IE, right-click > Properties, then copy the Address (URL).
You'll know you copied the correct address if it ends in .svg.
I don't understand what you're asking: "How a work in progress topic is managing better images uploaded in a personal gallery folder?"
Are you asking how the gallery can be used to display works in progress, at different stages of the drawing? I've had a couple of thoughts about that.
One is that images of the same drawing at different stages of completion, may or may not be of interest to all viewers. Some people might find it quite helpful, beneficial or instructive to their own growth as an artist (or whatever profession or avocation). Others might not find it interesting at all. And some people might even think a WIP image is "ugly". So it's up to you, the album owner, to make your best assessment, and decide what to do. To me, I'm not concerned much with what others think about it. If they don't like it, they don't have to look at it, lol.
So for example, you could have an album for 1 single image, where you upload several to many WIPs, as the image progresses. Or maybe you could have an album for all your WIPs. Or of course, you don't have to use the IC gallery. You could upload your WIPs to any image host, and insert the URL provided by that host, in the message.
Or another idea. (Unless and until I find out about this privilege potentially being abused,) private albums can be created and maintained in the IC Gallery! Then you could upload all your WIPs in a private album which only you can see. Although......hhmmm..... if the album is private, I wonder if only the album owner could see the image?? I'll have to do a test on that.
Or maybe I misunderstood your question, lol??