Wallapop is a mobile-first marketplace: most buyers browse on a phone, often on patchy data. Heavy photos make your listing slow to load, bury it under faster-loading competitors, and sometimes fail to upload entirely when the connection drops halfway. Skwish compresses images in your browser with a live before/after readout, so you can keep a crisp, honest photo of the item and still cut the file to a fraction of its weight. Prepare a batch of items and export them as one ZIP. Nothing leaves your device.