Let's say you're starting with images:
Code:
<img alt="" src="../Images/image001.png" />
[...]
<img alt="" src="../Images/image098.png" />
<img alt="" src="../Images/image099.png" />
This is potentially what I would do:
1. Go into
Tools > Reports > Image Files.
2. Look through the images, any that are duplicate fleurons:
Right-Click > Delete From Book:
3. Once you get rid of all the fleurons, then return back to the main Sigil window.
Open the Images folder, Shift-Click to highlight all images, Right-Click > Rename:
4. Rename to something completely different. Like "TempImages001".
Now, all your surviving images will be named "TempImages001", "TempImages002":
Code:
<img alt="" src="../Images/TempImages001.png" />
[...]
<img alt="" src="../Images/image098.png" />
<img alt="" src="../Images/TempImages002.png" />
while all the non-existent fleurons will be under the old naming convention.
5. Now you can use Regex to easily change all the old image code into "fleuron.png":
Search: <img alt="" src="[^"]+image\d+\.png" />
Replace: <img alt="" src="../Images/fleuron.png" />
6 (Optional). Now go through and give your surviving images all human-readable names.