Each MMS sample file must sit under its per-type size ceiling

The requirementstatement

Every attached MMS sample file must be at most 500 KB for GIF, JPEG and PNG images, and at most 600 KB for any other media type.

Severityseverity: BlockingBLOCKINGBreaking this rule gets the submission rejected. There is no partial credit.
When it bitesphase: Gates approvalapprovalGet this wrong and the brand or campaign is refused at registration.
What is checkedobject: campaign.mms_sample_media
Where it liveslayer: Message contentMESSAGE_CONTENT
How Ekas settles itdetectability: DeterministicDETERMINISTIC; Settled in code from the values you submitted. No model involved, no judgement call, same answer every time.
What the fix involvesfailureClass: Fix the fieldRETRY_FIELD; A better value in the form fixes it. Ekas can rewrite it and re-check.
Who requires itauthorities: AWS
When it appliesapplicabilityText: Applies when `mmsEnabled` is true.

Why this rule existsrationale

The ceiling is the handset's, not the reviewer's: an oversized MMS is transcoded or dropped somewhere in the carrier chain, so the recipient gets a broken message and the sender never learns why. Registration rejects it up front instead. This catches out businesses who attach the print-resolution asset their designer handed over, because nothing about a 3 MB PNG looks wrong until it is measured.

How to fix itremediation

Re-export each attachment under its ceiling — 500 KB for GIF, JPEG and PNG, 600 KB for everything else — and re-upload. Resizing to 1200 px on the long edge and exporting at 80% JPEG quality clears it for almost any promotional image. Done when every file in the sample media list reports a size below its own limit.

A compliant exampleexample

acme-summer-sale.png re-exported at 1200x628 → 214 KB (limit 500 KB for PNG).

Common mistakespitfalls

The tighter 500 KB bound is keyed on the file type, not on it being an image: a WebP or a short MP4 gets the 600 KB allowance, a PNG does not.

Provider rejection codescodes

The code you get back when this rule is what failed, and whether that provider lets you resubmit.

Provider	Code	Resubmit
AWS	INVALID_FIELD_VALUE	Yes

Rules you will hit next

2 other rules read campaign.mms_sample_media. Fixing one field to satisfy a single rule is how a resubmission trades one rejection for another, so read these before you change anything.

MSG-018An MMS campaign must attach at least one sample media fileBlockingBLOCKING MSG-020MMS sample images must not be placeholder or stock artworkHighHIGH MSG-008Opt-in confirmation must be 20–255 charactersBlockingBLOCKING MSG-009HELP reply must be 20–255 charactersBlockingBLOCKING MSG-011Opt-out confirmation must be 20–255 charactersBlockingBLOCKING MSG-031Sample messages must be in EnglishBlockingBLOCKING

All message content rules

MSG-019 is one of 122 message content rules in the 915-rule 10DLC registry. Free to cite under CC BY 4.0.