That's perplexing. Just out of curiousity: Is everything a vector, or is it a mix of vectors and bitmaps? It appears that some of the components resized properly, where others did not.
Since you know what dimensions you're shooting for, you could try reversing the order of things: resize, then trim. First figure out the percentage by which you were reducing the trimmed image size: 1680 / 2071 = 81.12%. Now apply that percentage to your initial image size: 5000 x 2048 becomes 4056 x 1661. Do the same sizing discrepancies occur? If not, then apply the Trim Canvas command, and you should be good to go.
Alternatively, if you're resizing this graphic for output, you could simply use the Image Preview dialog instead (after trimming).
Another troubleshooting idea: Have you tried saving the graphic immediately after applying the Trim command, and then resizing?
Finally, how about using Modify > Transform > Numeric Transform... and then choosing either Resize or Scale?
Sorry it took me so long to reply. Yes, everything is vector. There are no bitmap elements on in the graphic. I can't resize then trim due to other objects that are not currently in view being used in conjunction with this image. If I resize, then trim the canvas doesn't get trimmed to only the viewable area.
The 'Image Preview' option works great. It actually does better what I was trying to do. As I've only been working with fireworks for the past month, it's been a great learning curve; especially coming from opensource Gimp which is raster image only anyway.
Thanks for the input. Sure would like to find out why my images are doing this though.
I'm glad you got something to work.
My thinking was that perhaps somehow the Trim command was causing the glitch... that's why I suggested resizing first, to see if the same problem occurred. Or trying the Numeric Transform command, in case the Image Resize command is at fault. Perhaps the cause of this glitch will reveal itself to you later, in time. Otherwise, it could be a bug in the software, and it's good to narrow down exactly what triggers it.
In a pinch, you can use Modify > Canvas > Canvas Size... to trim the canvas, but you need specific dimensions. Matt Stow once made his own "Fit Canvas and Trim Canvas" commands, but I have to admit I never felt a need for them:
(See the February 18, 2008 posting for a description and download link.)