标签：#imageprocessing

ImgProxy is an open-source image-processing server — resize, convert, and transform images on the fly via URL parameters, ideal as a caching layer in front of a CDN or web app. This guide builds ImgProxy from source on Ubuntu, runs it as a systemd service behind Nginx with TLS, walks through its URL processing options, and secures it with signed URLs. Prerequisites: an Ubuntu server, a domain A record (e.g. imgproxy.example.com ), non-root sudo user. Install ImgProxy ImgProxy uses libvips for image processing; this builds it from source with Go. $ sudo add-apt-repository ppa:dhor/myway $ sudo apt update $ sudo apt install libvips-dev -y $ sudo snap install --classic --channel = latest/stable go $ git clone https://github.com/imgproxy/imgproxy.git $ cd imgproxy $ sudo CGO_LDFLAGS_ALLOW = "-s|-w" go build -o /usr/local/bin/imgproxy Create the environment config: $ sudo touch /usr/local/bin/imgproxy.env $ sudo nano /usr/local/bin/imgproxy.env IMGPROXY_BIND = :8080 IMGPROXY_NETWORK = tcp IMGPROXY_READ_TIMEOUT = 10 IMGPROXY_WRITE_TIMEOUT = 10 IMGPROXY_WORKERS = 2 IMGPROXY_REQUESTS_QUEUE_SIZE = 0 IMGPROXY_QUALITY = 100 IMGPROXY_PREFERRED_FORMATS = webp,jpeg,png,gif,avif IMGPROXY_LOG_FORMAT = "pretty" IMGPROXY_LOG_LEVEL = "INFO" IMGPROXY_WATERMARK_URL = https://example.com/watermark.png IMGPROXY_WATERMARK_OPACITY = 1 Key settings: IMGPROXY_WORKERS should be ~2× your vCPU count; IMGPROXY_REQUESTS_QUEUE_SIZE=0 means unlimited queueing; IMGPROXY_WATERMARK_URL points at whatever image you want overlaid when watermarking is enabled. Point ImgProxy at the config and test: $ export IMGPROXY_ENV_LOCAL_FILE_PATH = /usr/local/bin/imgproxy.env $ cd $ imgproxy WARNING [2024-05-28T00:40:42Z] No keys defined, so signature checking is disabled WARNING [2024-05-28T00:40:42Z] No salts defined, so signature checking is disabled INFO [2024-05-28T00:40:42Z] Starting server at :8080 Stop it with Ctrl+C once verified, then set it up as a service. Run ImgProxy as a systemd Service $ sudo useradd

Disclosure: I work on Passlens, a browser-first passport and ID photo maker. This post is about the product decisions behind that workflow, not a neutral review of every tool in the space. A passport photo looks simple until you try to make one that an upload form will actually accept. It is a headshot, yes, but it is also a small chain of constraints: physical size, pixel size, background, head position, print scale, and whatever the destination country's portal decides to reject that week. That is why generic photo editors feel slightly wrong for this job. They can crop. They can resize. They can export. The hard part is not any one of those actions. The hard part is keeping all of them tied to the document rule the user picked. The unit problem For developers, document photos are awkward because two units matter at the same time. A user may need a 2x2 inch passport photo. A visa portal may ask for 600x600 pixels. A print sheet may need 35x45 mm photos at 300 DPI. These are not the same request, but people often treat them as if they are. If the app only thinks in pixels, the print can come out the wrong physical size. If it only thinks in millimetres or inches, the digital upload can be rejected for the wrong pixel dimensions. A good workflow has to keep both ideas alive: the document size and the export target. That is the main reason Passlens keeps presets and print layouts as first-class pieces of the workflow instead of treating them as labels on a crop box. The crop is not the output Another small trap: the crop the user sees is not always the final output. For a digital upload, the crop usually becomes one image file. For printing, the same crop may become several photos arranged on 4x6, A4, or Letter paper with spacing, margins, and optional cut marks. If that print sheet is scaled by the browser or printer dialog, the whole thing is wrong. So the editor needs to separate three things: the face and shoulder crop the finished document-photo size the print s