This program converts ![]() markdown image syntax to an img tag with a u-photo microformats2 class.

markdown_jekyll_to_img_tags.py

import os

for filename in os.listdir("_posts/"):
    if ".md" in filename:
        with open("_posts/{}".format(filename), "r") as file:
            line_number = 0
            line_to_replace = ""
            lines = list(file.readlines())
            final_img_tag = ""
            for l in lines:
                line_number += 1
                # Only search in first 10 lines because u-photo is for featured images and I kepe the featured image in the first 10 lines of my blog posts if I specify one
                if line_number > 10:
                    break
                if "![" in l:
                    # Get alt text and image URL

                    line_to_replace = l
                    find_last_square_bracket = l.find("]")
                    alt_text = l[2:find_last_square_bracket]
                    path = l[find_last_square_bracket+2:]

                    new_path = path.replace(")", "").replace("\n", "")
                    
                    # Create new img tag

                    final_img_tag = '<img src="{}" alt="{}" class="u-photo">'.format(new_path, alt_text)

                    # Stop loop when the markdown image is found because I only want to replace one

                    break

            new_file_content = ""

            # Replace the line_to_replace (old markdown line) with the new img tag

            for l in lines:
                if l == line_to_replace:
                    new_line = l.replace(l, final_img_tag)
                elif l != "\n":
                    new_line = l.replace("\n", "")
                else:
                    new_line = l.strip()

                new_file_content += new_line + "\n"

        # Write amended file

        writing_file = open("_posts/{}".format(filename), "w+")

        writing_file.write(new_file_content)

        writing_file.close()