Editing Slices in PSE 15+
Now that the image is sliced, you may need to modify some of the slices.
1. To choose (activate) a specific slice, make a selection inside its borders with the Rectangular Marquee tool as shown on figure 1/1 (the selection corners shouldn't touch the slice boundaries). Then run "Select Marked Slices" script (fig. 1/3).
To select an additional slice (for example, to add slice #52 to already active slice #32), mark it with the Rectangular Marquee tool (fig. 1/1) and then hold down [Shift] key while running the "Select Marked Slices" script (fig. 1/3).
To select several adjacent slices at once, mark the whole range with the Rectangular Marquee (on fig. 1/2: slices #32, #42, and #52), and run "Select Marked Slices" script (fig. 1/3).
NB. Using the "Select Marked Slices" script isn't always necessary. In most cases, you can just mark the needed slice(s) with the Rectangular Marquee tool and then run "Delete", "Combine", "Divide", "Promote", or "Slice Options" script.
2. To assign a hyperlink to the selected slice, run "Slice Options" script and, in the dialog that opens, type the desired address into "URL" field (fig. 2).
3. To reposition or resize the selected slice, open "Slice Options" dialog and edit the corresponding fields in the "Dimensions" area (fig. 3).
4. To align the created slices to each other, select 2 or more slices, run "Align Selected Slices" script, and select an option in the dialog that opens (fig. 4).
Tip. To keep the HTML-table structure simpler, it is recommended to avoid overlapping and unnecessary slices.
5. To remove unnecessary elements, select one or more slices and run "Delete Selected Slices" script (fig. 5).
6. For joining several adjacent slices, select them and then run "Combine Slices" script (fig. 6).
7. If you need to convert an "auto-slice" to "user-slice", mark it with the Rectangular Marquee tool and run "Promote to User Slice" script (fig. 7).
8. To re-use the created slices later on, save the document as PSD file.