Anyone else have problems linking images?

I'm on the freebie plan so limited to 800px long dimension or 250kb. I size all my images on my own site to these dimensions in order to not need to resize to post on NSN. I always post via URL link. I routinely run into refused  posts and the message always says I'm over the 250kb limit. I can understand if I save to 240k it could be close enough to be seen differently by different software etc. But after having the problems I'm now routinely resizing to no more than 220k or so and still running into the problem. Is there some glitchy little nuance that I'm missing?

Dan, can you PM me an example URL or two linking to images that are being blocked for you? I'd like to check a couple of things.

Thanks, Royce for helping me resolve this issue.

For any onlookers, I am a Zenfolio user and the problem I was having is that when linking to images in my Zen galleries, the software on that end was causing the file sizes to change (though not the visible images) in an unpredictable manner such that the file size indicated in my Zen account (or when I donwloaded the files from Zen) were different than those being linked to NSN. Maddeningly sometimes the file sizes are bigger, sometimes smaller. I'm sure it makes sense to an IT person but not to me....

Kudos to the excellent response from the NSN team in helping figure out what was going on here.

Cheers, Dan. Glad to be able to help sort through it...