The iPhone SE Wallpaper size (750×1334px)
750x1334 pixels is the native resolution of the iPhone SE, shared with the classic iPhone 6, 7, and 8. Unlike the tall modern iPhones, the SE uses a shorter, more traditional 9:16 Retina display with home-button-era proportions, so it is noticeably less elongated than the 19.5:9 screens on recent models.
That difference is exactly why wallpapers made for newer iPhones do not fit the SE cleanly; they are too tall and end up cropped or zoomed. Resizing to a native 750x1334 gives the SE the precise 9:16 canvas it expects, filling the compact screen edge to edge with your whole composition intact and no distortion.
Because the SE screen is smaller and lower resolution than the Pro models, there is no benefit to a huge source; the panel simply cannot show more than 1334 lines of height, so resizing your photo to this exact size keeps it crisp and the file light. Plan for the iOS layout: the lock screen shows the clock in the upper-middle and the home screen fills its lower two-thirds with icons and the dock. Keep faces and focal points in the central band. This tool resizes entirely in your browser, so your photo is never uploaded, it is free, and your original quality is preserved while the file is fit to the 9:16 SE frame. Apple can change specs, so verify before exporting.