Presets and their sources

The width 1920 is the default value in the project specification 7.2. There is no platform documentation for it — the number is a setting of this project, not an outside requirement. The width is a budget, not a requirement — hence `fit: "max"`.

The target size of 100 KB is the preset itself; the value is set this way in the project specification 7.2 and counts in base 1024 (102,400 bytes). There can be no outside source for it. The resolution stays untouched — it is reduced only when the target size cannot be reached through the quality setting alone (6.6). Without a target resolution `fit` has no effect; it is set to “max” because a requirement without dimensions would not be one.

The target size of 500 KB is the preset itself; the value is set this way in the project specification 7.2 and counts in base 1024 (512,000 bytes). There can be no outside source for it. The resolution stays untouched — it is reduced only when the target size cannot be reached through the quality setting alone (6.6). Without a target resolution `fit` has no effect; it is set to “max” because a requirement without dimensions would not be one.

The target size of 1 MB is the preset itself; the value is set this way in the project specification 7.2 and counts in base 1024 (1,048,576 bytes). There can be no outside source for it. The resolution stays untouched — it is reduced only when the target size cannot be reached through the quality setting alone (6.6). Without a target resolution `fit` has no effect; it is set to “max” because a requirement without dimensions would not be one.

The width 1600 is set in the project specification 7.2. There is no authority for an attachment limit — every provider and every company gateway sets its own. 2 MiB (2,097,152 bytes) is therefore a project setting: an attachment is sent base64-encoded and grows by about a third, so a 2 MiB image becomes a message of about 2.8 MiB. Even a conservative 10 MB gateway carries three of them plus text. The unit follows the size presets, which count in base 1024 under 7.2. The width is a budget — hence `fit: "max"`.

The dimensions 1200 × 630 are set in the project specification 7.2. An outside source is conceivable, but none is on file; this is therefore a project value, not a declared platform requirement. `fit: "max"` despite the fixed format of the link preview: `exact` promises “exactly 1200 × 630 px”, and the engine cannot keep that promise. If the aspect ratio differs, it fits the image into the frame instead of cropping (cropStrategy "fit", 2.2) — a 4:3 image then becomes 840 × 630, not 1200 × 630. A data model must not claim a capability that does not exist; that is why the budget stands here (decision 53). Whether and how `cropStrategy: "center"` is built will be decided once the four platform presets with a real need for cropping are verified.

The width 1600 is set in the project specification 7.2. No platform source is on file; WordPress creates its own responsive variants from the upload anyway. The width is a budget — hence `fit: "max"`.

Shopify Help, page on product media types — paraphrased: on September 16, 2026 the page could not be read verbatim, only through a summary. According to it: square product images usually display best at 2048 × 2048 px; product and collection images may be up to 5000 × 5000 px or 25 megapixels and must stay below 20 MB. As a target file size, the 20 MB limit is read as decimal (20,000,000 bytes) — the smaller of the two possible readings, so it is within the limit either way. The 2048 px are a recommendation next to an upper limit of 5000 × 5000 px, not an exact requirement — hence `fit: "max"`.

Instagram Platform, IG User Media reference — paraphrased: on September 16, 2026 the page could not be read verbatim, only through a summary. According to it: at most 1440 px wide, wider images are scaled down by the platform; at least 320 px wide, narrower ones are scaled up; at most 8 MB; aspect ratio between 4:5 and 1.91:1; color space sRGB, other color spaces are converted; JPEG as the only format. This is the documented publishing interface. Because the reference names a maximum width that is scaled down when exceeded, the preset uses `fit: "max"`.

LinkedIn Help, page “Add or change the cover image on your profile”, section “Cover image specifications”: “JPG or PNG file”, “Lesser than 8MB”, “1584 (w) x 396 (h) pixels (recommended)”. The 8 MB limit is read as decimal (8,000,000 bytes) — the smaller of the two possible readings. The dimensions carry the addition “(recommended)”: a recommendation, not a requirement — hence `fit: "max"`.

YouTube Help, custom video thumbnails: “We recommend your custom thumbnails: Have a resolution of 3840 x 2160 pixels for videos […] with a minimum width of 640 pixels for videos”, “Be uploaded in image formats such as JPG or PNG”, and for videos “an aspect ratio of 16:9”. The formats are examples; this preset allows only the two named ones. For file size the page gives two limits, depending on the device: “Mobile: 2 MB for video thumbnails” and “Desktop: 50MB for video, Shorts, and podcast thumbnails”. The smaller one is used, read as decimal (2,000,000 bytes), so the file passes either way. The resolution is a recommendation next to a minimum width of 640 px, not an exact requirement — hence `fit: "max"`.