Tomi,
The software platform is hired in from another company. They sell a basic forum and the gallery is a bolt-on. It is not therefore integral with the forum, as it was on the old platform.
The software developers wrote the gallery software without a search facility because they did not think that it was needed and would have required extra work to incorporate it.
Admin have told us that the 'issue' is being referred to the developers but I don't think it will be sorted anytime soon if at all.
I believe that there is a third party work-round available and I have seen it in use, but it is not part of the package which Verticalscope want to use apparently.