Recently I was looking for a way to translate slides from the popular Phothoslide GK2 Joomla component and noticed there was not so much information out there about it, after a few minutes I found out that it was quite easy to do it, just follow this steps:
1) In the backend of your Joomla site go to Components -> Gavick Photoslide GK2
2) If you have a group "main_group_EN" then create a group for your translation like "main_group_ES" (Spanish translation) by clicking on "Add Group"
3) Add the translated slides to this new group
4) Go to Components -> Joom!Fish -> Translation
5) Choose your language in the "Languages" combo box
6) Choose "Modules" from the "Content elements" combo box
7) Find and open the "Gavick News Image I" module
8) Find the "Slides group" combo box and choose the new translated slides group you created on step 2 (main_group_ES)
8) Tick on the "Published" option and save the changes
That's it! now you can translate your slide show to any language you want ;)