There is an update.
1. Added new tags <SC_IMAGE_PREVIOUS_DATETIME_FORM> and <SC_IMAGE_NEXT_DATETIME_FORM> for formated date of previous and next image
2. Added new tag <SC_BROWSE_CATEGORY> which gives form with selectable category (thx for inspiaration to RobbieMc)
3. Added configuration variables inside script which tell if code for form with selectable category should be executed (for this who dont use this form it will speed up addon) and if you want to get current image ID under sc_image_next_id or sc_image_previous_id when you are watching image at one of ends (once more time thx to RobbieMc)
1) Now you (RobbieMC) got variable for it in configuration part.
Going back to this topic - you got SC_IMAGE_NEXT_LINK_TXT AND SC_IMAGE_PREVIOUS_LINK_TXT which shows up only if there are some pictures.
You can use SC_IMAGE_NEXT_LINK AND SC_IMAGE_PREVIOUS_LINK just like above but for rest of non-text elements (i.e. for images linking).
2) a) - I left it for future release
2) b) - Now it is implemented. I was trying to get one smart query for MySQL < 4.1 for a whole day but I didnt found such. There is only "small" automatic optimalization for MySQL >= 4.1 which speeds up query ~10%.
PS By default configuration is set to disable 1) and 2) b). Not everyone wants such behaviour and slower scripts.