I know what you mean about uploading pictures. I have the same problem as my only digital camera is a cellphone and the pix just will not load into the site. My computer is ancient (about 1999 vintage) and won't install any of the new programs to work with the picture files for compression etc.
On the subject of hul colours, to a great extent I feel that as long as you get close enough that it looks right to the eye, you're ok.
That's because during the war, the exact colours of equipment changed as they found that what worked and what didn't. So an early war boat may have a colour called dunkelGrau slightly different than a late war boat.
Also, and especially later in the war when getting a boat out to the front was more important than getting the colours exact, shipyards would use whatever was available as long as it was close to the desired colour. You might see this with repair work done to damage being almost, but not quite, the same colour.
And finally, salt water and sun are very harsh on paint so a boat on it's third patrol without being repainted might be a different colour when compared to the same boat on it's first patrol, before fading, weathering, rust, oil, diesel fuel, grime, etc got at the paint. The upper and horizontal surfaces would get lighter, the vertical surfaces might get darker and the edges would get either lighter or darker depending on the wear and what came into contact with them.