Photosounder is an image-sound editor and synthesizer developed by Michel Rouzic, who has been the sole person behind the project since 2008. The flagship Photosounder application takes an entirely image-based approach to sound creation and editing, allowing users to convert any sound into an image and to synthesize new sounds from images. Its toolset spans spectral editing, sound isolation, extreme time stretching, pitch shifting, vocoding, and a range of unusual effects such as melody flattening, interval stretching, sound rotation, and sound blurring.

Alongside the main Photosounder editor, the brand develops SplineEQ, a spline-based linear-phase equalizer plugin, and Spiral, a musical spectrum analyser that visualizes pitch and harmonic content on a logarithmic spiral. The software is available for Windows and macOS, with Linux support via Wine, and is sold direct as well as through retailers like Plugin Boutique.

Photosounder occupies a niche corner of the audio software world focused on spectral and image-based sound design, and has built a small but dedicated following among sound designers, experimental musicians, and producers interested in extreme audio manipulation. The KVR Audio forum hosts an active community section dedicated to the software.

Photosounder has 3 products cataloged on Equipboard, including EQ Plugins, Spectral Analysis Plugins, and Synth Plugins. Their gear is featured by 2 artists, with the strongest followings in Electronic. Notable users include Fox Stevenson and Bustre.