Drop your citizenship photo, get a JPEG between 70 KB and 3.5 MB at the preferred 1200×1600 pixels — the Home Affairs online-application format. Nothing is uploaded; it all runs in your browser.
Online Australian citizenship applications take one digital photo: a JPEG between 70 KB and 3.5 MB, with a preferred resolution of 1200×1600 pixels, no more than 6 months old. That applies to citizenship by conferral (uploaded under “Photograph” in the online form) and to citizenship by descent and evidence-of-citizenship applications, which upload a digital copy of the same photo endorsed on Form 1195. This page is preset to exactly that window and resolution. Home Affairs recommends having the photo taken by a professional passport photo provider — it names Australia Post — and getting a digital copy emailed to you. If that emailed JPEG is already between 70 KB and 3.5 MB, upload it as-is and close this tab.
First: the file is over 3.5 MB — common for a full-resolution studio JPEG or a modern phone photo. PixFit binary-searches for the best JPEG quality that fits under the cap; at this generous a ceiling the result is visually indistinguishable. Second: it's an iPhone HEIC — drop it straight in, it's decoded in your browser and comes out as the JPEG the portal wants. Third: it's under 70 KB, which almost always means it went through WhatsApp or a messaging app that recompressed it. PixFit can pad a JPEG up to the 70 KB floor with a spec-valid comment segment, but padding adds no detail — ask for the original file (“actual size”/document mode) or the provider's emailed copy instead; the quality requirements still apply to what's in the pixels.
1200×1600 is the spec's preferred resolution, not a hard rule, so this page presets it: if your photo is a different shape it's center-cropped to 3:4, with a warning showing both ratios. A standard 35×45-style portrait crops to 3:4 almost losslessly. But if you'd rather not touch the framing at all — a reasonable instinct with an identity photo — clear the Exact size field and PixFit will only fix the bytes; the 70 KB–3.5 MB window is the enforceable part. Don't upscale a small photo to hit 1200×1600: resampled pixels add no detail, and an under-sized soft photo needs retaking, not resizing.
For online applications Home Affairs is explicit: a scan of a photo, or a photograph of a photo, is not acceptable. No file tool can fix that — if all you have is a print, go back to the provider for the digital file or have a new photo taken. (The paper application route is where prints belong: 35–40×45–50 mm, face 32–36 mm chin to crown — a different spec this page doesn't handle.) Note the photo must also be unedited: Home Affairs' list says don't remove the background, moles, wrinkles, scars or red eyes. Re-encoding to fit the byte window is file plumbing, the same thing a photo kiosk does; running the photo through an “enhancer” is what gets it rejected.
Everything else on the requirements page: full face centred and straight-on, neutral expression with mouth closed, hair off the face, uniform lighting with no shadows or reflections, neutral or light-grey background that contrasts with your face, glasses removed (vision impairment alone is not an accepted reason to keep them), head coverings only for religious reasons and only if the whole face shows. Check your result against the current list at immi.homeaffairs.gov.au before you submit. Two neighbouring specs to not confuse with this one: other supporting documents on a citizenship application should be JPGs limited to about 500 KB each (visa applications via ImmiAccount allow 5 MB), and the Australian passport application accepts no digital photo upload at all — passports use printed photos only. Applying elsewhere? See the UK passport and Canada citizenship pages.