My go-to local app image optimizer has long been ImageOptim. It’s Mac-only (and free), but they suggest alternatives for other platforms. I reach for ImageOptim usually when I want to optimize a whole bunch of images in a batch. For one-offs, you can’t do much better than Squoosh, a great progressive web app (PWA).
I haven’t seen much innovation in this space in a long time, but recently just saw Convert & Compress and it’s pretty good! It’s got a nice UI for looking at before/after results like Squoosh has, but also does batch processing. The one review left so far mentions SVG support, which I agree would be nice. ImageOptim does that, as does the PWA SVGOMG. Convert & Compress is free-for-now and looks reasonably priced once it’s not anymore.
If you don’t like the UI or features, it feels like this is the kind of app that would be good vibe coding practice.
Got into it lately, too, but it is hard to break away from imageoptim – this one also has a cli option and a web service https://imageoptim.com/mac
It’s cool to see someone else read that alternatives page, although I personally use FileOptimizer since Windows is my daily driver. (Seemingly have been using it for ~5 years too, since it says I’ve been a user since 14.20.2553)
Recently I’ve been converting some more newer batches of images to AVIF. If you want Squoosh’s AVIF converter but run locally you can use ImageMagick.
From what I’ve seen online ImageMagick uses the same AVIF compressor under the hood as Squoosh and outputs similar sizes when both are at default settings and both tuned to the same quality settings. Not sure if my advice is useful for Mac users though since I’m not familiar whether ImageOptim already supports AVIF though. I just randomly wanted to share this regardless
magick mogrify -format avif *.png *.jpg *.webp
.etc