Convert and compress images on your phone (no app needed)
You don't need a PC — or an app — to convert, compress, or resize images. Here is how to do it right from the browser on iPhone or Android, plus the phone-specific pitfalls to know.
No app installation required
Searching for an "image converter app" surfaces dozens of options, many heavy on ads or photo-library permissions. Browser-based tools do the same job with nothing to install.
Filewisp's tools all run in mobile Safari and Chrome. Processing happens on the phone itself — images are never uploaded — which makes them comfortable to use for private photos.
The basic flow (iPhone and Android)
① Open the tool page in your browser, ② tap Choose File and pick from your photo library, ③ tap convert or compress, ④ download from the result screen. That's all.
On iPhone, downloads land in the Files app under Downloads; on Android, in the Download folder or via the notification. They don't appear in the Photos app automatically — worth remembering.
The #1 phone use case: HEIC to JPG
iPhone photos are HEIC, which submission forms and Windows users frequently reject. Being able to convert to JPG from the phone's browser saves the day when you're away from a PC.
Resume photos, marketplace listings, application attachments — "JPG only" comes up more often than you'd think. Bookmark the tool for those moments.
About data usage and battery
Browser tools sound like they upload, but ours don't: conversion runs in the phone's browser engine, so data usage is just the page load — even for large photos.
Processing does use the phone's CPU, so very large batches drain some battery. A few to a dozen images is perfectly practical on a phone; for hundreds, a PC is more comfortable.
Tips for compressing on a phone
Social and marketplace apps usually compress for you, but email and application forms don't. Phone photos run 3–8 MB; resizing to ~1600 px on the long edge plus ~80% quality compression typically lands around 1 MB.
Use the preview to zoom in and check for artifacts on the phone screen before downloading — that avoids re-dos.
If something doesn't work
If the photo picker shows nothing, check that the browser has photo access permission (a dialog appears on first use). Private browsing can also change download behavior.
Extremely large images (100-megapixel panoramas) or hundreds of files at once can hit mobile memory limits. Split the batch or switch to a PC for those.
Bottom line: bookmark it and skip the PC
Everyday image chores — converting, compressing, resizing, making PDFs — all work straight from a phone browser, with no app ads or permissions to worry about.
Filewisp is optimized for mobile, with 45+ free tools. Add your most-used ones to the home screen and they behave like apps.