1. What template are you using? As your referring to roksprocket I can only assume it's a Gantry 4 based template(and I'd guess at Myriad)? If it is, and you're just starting out, I'd recommend that you consider using a Gantry 5 based theme instead (there is a Gantry 5 version of Myriad). This is because Gantry 4 WILL NOT be made to work on Joomla 4 whereas Gantry 5 WILL (shortly). Gantry 5 is also much more flexible and powerful than Gantry 4. Furthermore, roksprocket is in it's twilight years as it uses the very old "Mootools" (which often conflicts with modern jQuery based programs). All that said, you can carry on with Gantry 4 on Joomla 3.10.x for a further two year (at which point Joomla will drop support for J3.10), Gantry 4 is stable and roksprocket is stable on that Gantry 4.
2. You should be removing the "fp-preset-images" class anyway as that is for demo purposes only.
Please search forums before posting. Please make sure your post includes the version of the CMS you are using and a link to the problem. Annotations on screenshots can also be helpful to explain problems/goals. Please use the "secure" tab for confidential information.