When Ted designed our RoboHelp2Wiki extension he used a separate option to upload images primarily to save testing time and possible some bandwidth.  I validated the separate option and was able to upload 500 test images (various sizes) in a few minutes. Your speed will vary!

To duplicate:   

1. Download the RoboHelp2Wiki MediaWiki extension
2. Make sure all images have unique names.
3. Place all image files in a single sub-directory under the working directory named images
4. At the command line type:   java -jar RoboHelp2Wiki.jar <workingDirectory> image

Click Here to request a copy of the tool and source code.

RoboHelp2Wiki V 0.9 converts Macromedia RoboHelp Topics to MediaWiki pages. For this release, most of the structural and object elements are converted to proper wiki counterparts. Stylesheets and javascripts are mostly discarded. Display related markups, such as font size, colors, appearances, are not retained in most cases.

RoboHelp2Wiki is a product of The JK Group, Inc. released under GNU General Public License 2.0.
Requires Java Runtime Environment (JRE) 5.0 or later, RoboHelp HTML X5.0.2 Build 801, and MediaWiki Version 1.7 or 1.8.

RoboHelp is a product of Adobe Systems Incorporated.,
Mediawiki is a wiki engine released by Mediawiki.org,
Java Runtime Environment (JRE) 5.0 is a product of Sun Microsystems