Quick Start

CloudPhoto resizes, transforms, compresses & optimizes your images on-demand from a single URL. The v2 API uses query parameters for maximum flexibility — works from any language, no SDK required.

https://cdn.cloudphoto.io/<token>/img?<params>&url=<source_image_url>

Golden rule — url is always the LAST parameter. Everything after url= is the source image URL, including its own query string (e.g. Centris media.ashx?id=...&t=pi). All CloudPhoto parameters come before url=. The source URL is taken raw — no encoding needed.

Minimal example — resize to 600px wide, served as WebP:

https://cdn.cloudphoto.io/demo/img?width=600&url=https://samples-photos.com/tennis.jpg

The default output format is WebP (universal, lighter than JPEG). Add &f=auto to serve AVIF to browsers that support it (with automatic WebP fallback), or &f=original to keep the source format.

Production URLs go through the CDN cdn.cloudphoto.io (cached, fast). The examples below hit the origin app.cloudphoto.io directly — both expose the same API.

Parameters

Param	Description
`token`	Your CloudPhoto customer token (first path segment).
`width` / `w`	Target width in pixels. Alone, keeps the aspect ratio.
`height` / `h`	Target height in pixels. Alone, keeps the aspect ratio.
`fit`	Resize operation (see Operations). Omitted → derived from the dimensions.
`ar`	Target aspect ratio (`16:9` or `1.5`). With a single dimension, derives the other and crops to the ratio.
`dpr`	Device pixel ratio (1–5) for retina. Multiplies the requested dimensions.
`f`	Output format: `webp` (default), `avif`, `jpg`, `png`, `original`, or `auto` (negotiated from the `Accept` header).
`q`	Quality 1–100, or `auto`. Defaults tuned per format.
`g`	Gravity / focus for crop (see Filters → gravity), including `entropy` (content-aware smart crop, no AI).
`fx`	Dot-separated chain of filters (see Filters), e.g. `brightness120.saturation140.blur3`.
`org_if_sml`	`1` = never upscale: if the source is smaller than the target, serve it at its own size.
`md`	`1` = keep image metadata (EXIF/IPTC). Stripped by default for lighter files.
`ci_info`	`1` = return transformation metadata as JSON (format, dimensions, weight, cache, timings) instead of the image.
`force`	`1` = bypass cache and regenerate.
`url`	The source image URL. Always last, taken raw.

Operations

The fit parameter selects the resize behavior. When omitted: width+height → crop, a single dimension → width/height.

Operation	Description
`none`	No resize — only re-encode / apply filters.
`width`	Resize to a width, height proportional.
`height`	Resize to a height, width proportional.
`crop`	Fill the exact `width`x`height` box and crop the overflow (use `g` to choose the region).
`cover`	Force the exact `width`x`height`, ignoring the ratio (may distort).
`fit`	Fit entirely inside `width`x`height` (letterbox), padded with the `color` filter (transparent for PNG).
`bound`	Fit inside `width`x`height` keeping the ratio, without padding (output may be smaller).

Filters

Filters go in the fx parameter, separated by dots: fx=contrast20.colorFF0000.colorize30. The value is appended to the name without a separator, so values never contain a dot — gamma120 means gamma 1.2, opacity50 means 50%. Gravity has its own g parameter.

Geometry

Filter	Description
`rot<deg>`	Rotate by `<deg>` degrees. The empty area uses the `color` filter.
`flip`	Mirror vertically.
`flop`	Mirror horizontally.
`trim<fuzz>`	Remove uniform borders (`<fuzz>`% tolerance, default 5).
`border<n>`	Add an `<n>`px border in the `color` filter color.

Color

Filter	Description
`color<HEX>`	Color used by `fit` padding, `colorize`, `border` and `rot` (e.g. `colorFF0000`, `colortransparent`).
`colorize<0-100>`	Overlay the `color` tint at the given opacity.
`colorspace<X>`	Output colorspace: `sRGB`, `RGB`, `Gray`.
`grayscale`	Convert to grayscale.
`sepia<n>`	Sepia tone (default 80%).
`negate`	Invert the colors (negative).
`gamma<n>`	Gamma correction, `<n>`÷100 (`gamma120` = 1.2).
`brightness<n>`	Brightness, 100 = neutral (0–200).
`saturation<n>`	Saturation, 100 = neutral.
`hue<n>`	Hue rotation, 100 = neutral.
`contrast<0-100>`	Increase contrast.
`threshold<n>`	Black & white at the `<n>`% threshold.
`autocontrast`	Auto-stretch the tonal range.
`opacity<0-100>`	Global opacity (needs an alpha-capable output: PNG/WebP).

Effects

Filter	Description
`blur<n>`	Gaussian blur.
`sharpen<n>`	Sharpen (unsharp mask).
`pixelate<n>`	Pixelate in blocks.
`oilpaint<n>`	Oil-paint effect (`<n>` radius).
`vignette<n>`	Dark vignette (`<n>` spread).

Gravity (g parameter) — used by crop: Center, North, NorthEast, East, SouthEast, South, SouthWest, West, NorthWest, and entropy (content-aware smart crop, no AI — picks the most detailed region).

Responsive images

Use dpr for retina, and a plain HTML srcset with several widths — just vary the width parameter (no SDK, any framework):

<img
  src="https://cdn.cloudphoto.io/demo/img?width=800&f=auto&url=https://example.com/photo.jpg"
  srcset="https://cdn.cloudphoto.io/demo/img?width=400&f=auto&url=https://example.com/photo.jpg   400w,
          https://cdn.cloudphoto.io/demo/img?width=800&f=auto&url=https://example.com/photo.jpg   800w,
          https://cdn.cloudphoto.io/demo/img?width=1200&f=auto&url=https://example.com/photo.jpg 1200w"
  sizes="(max-width: 600px) 100vw, 800px"
  alt="Property photo">

f=auto lets the browser get AVIF/WebP automatically; each width is a separate cached variant.