What I suggest you to do is to write a simple batch file that processes files in the directory and outputs them in the given format.
For instance create file
run.bat and type the following command in it:
FOR %%F IN (*.png) DO @echo ^<img src='%%F'/^>
Now, you can run the command in the command-line, by entering:
If you want to save the results of the batch process into a file (such as images.html), you can use:
run > images.html
If you need to add more commands/processing steps, just edit the batch file.
For a good reference on commands (such has FOR loops), see Programming CMD on Wikibooks. Note that for complicated batch tasks, command-line interpreter may not be sufficient. For more complex batch programming, I encourage you to learn a real scripting language like Python.