Microbite Image Converter: Convert Existing WordPress Images to WebP / AVIF & Update DB

Why I Built This Plugin Like many developers, I was on a mission to speed up my WordPress sites through image optimization. I tested every major image plugin available, but they all shared the same frustrating approach: non-destructive conversion. These plugins would create optimized versions alongside your originals, bloating your media library. Some served image.jpg URLs that were secretly WebP files. Others created image.jpg.webp duplicates. It was a spaghetti mess of files, and I wanted something simpler: convert the actual files to WebP or AVIF and be done with it. So I built my own solution. The Technical Challenge What started as a simple idea quickly became a complex engineering problem: Challenge #1: WordPress stores image references in the posts and postmeta tables, with scaled image versions buried in serialized arrays. I had to convert files, validate them, and safely update these serialized structures without corrupting the database. Challenge #2: Not every theme and page builder uses WordPress’s standard image references. Many store image URLs directly in their own custom formats, some in JSON, some in serialized data, some in plain text. Challenge #3: I needed to search and replace image references across the entire WordPress database (similar to Better Search Replace), and with extreme caution. Different page builders store data in different formats, and one wrong move could corrupt everything. The Result After months of development and testing, I created a plugin that truly converts images, no duplicates, no hidden files, just clean WebP or AVIF files in your media library. It intelligently handles WordPress core, popular page builders, and even custom implementations, all while maintaining data integrity throughout the process.