The way companies communicate with their customers on mobile is undergoing a crucial transformation. Where text messages were previously limited to simple characters or heavily compressed MMS, today's customer journeys require crisp images, instructional videos, PDFs of invoices, and contact cards that can be saved with a single click.
For over two decades, MMS has been the primary standard for picture messaging, but today the technology is a bottleneck for modern brands. With Rich Communication Services (RCS), the old network limitations are replaced by a modern web-based file architecture.
In this article, we delve into how file transfer and high-resolution media work in RCS, why the transition from binary MMS compression to HTTP references is a game-changer, and how to optimize your formats for RCS Rich Cards.
MMS vs. RCS: How media is actually handled under the hood
To understand why RCS delivers a drastically much better visual experience than MMS, we need to look at the underlying technology of how media data is transported.
MMS models: Hard compression in the mobile network
When you send an MMS, the image or audio file is packaged directly into the message's payload and sent via the operator's MMSC (Multimedia Messaging Service Center). Because data is transmitted directly over the mobile network, operators set strict limits on file sizes – often between 300 KB and 1 MB.
To make an image or short video fit, the MMSC server performs aggressive compression. The result is often grainy images, blurry text in graphics, and videos with such low resolution that they are barely watchable. Furthermore, MMS lacks built-in and reliable support for complex document types such as PDF files.
RCS Models: File Transfer via HTTP References
RCS (based on the GSMA Universal Profile) completely departs from the concept of forcing binary data into the message signal itself. Instead, RCS uses the method File Transfer via HTTP:
- Upload: Our RCS API uploads the media file (image, video, PDF, or vCard) to a secure media server/CDN.
- Payload: The RCS message itself is sent as a lightweight payload consisting of JSON/XML containing a secure HTTPS URL to the file, the file size, MIME type, and a low-resolution preview (thumbnail).
- Download: The recipient's built-in messaging app (e.g., Google Messages or Apple Messages) receives the instruction and downloads the file directly from the media server in the background.
Since the file is downloaded over regular HTTPS connections, it is not affected by the compression algorithms of operating systems or mobile carriers. The recipient sees the content in the exact same quality as you uploaded it.
Overview Comparison: MMS vs. RCS for media
| Function | MMS | RCS |
|---|---|---|
| Maximum file size | Often 300 KB – 1 MB | Up to 105 MB |
| Transfer method | Binary data via MMSC | HTTP/HTTPS reference via CDN |
| Image & video quality | Heavily compressed / Low resolution | Full HD / 4K (Original Quality) |
| Document support (PDF) | No / Very limited | Yes, full support for viewing and downloading |
| Contact card (vCard) | Varying support / often uncertain | Yes, built-in support for .vcfr |
Format and Resolution: How to Optimize Your Files for RCS
Although RCS allows files of up to 100 MB, from a user and UX perspective it is usually best to optimize media files for fast loading time and seamless playback.
1. Images (JPEG & PNG)
- Aspect ratio: For RCS Rich Cards, it is recommended 16:9 (horizontal) or 1:1 (square) to fit perfectly in the chat window without taking up the entire screen.
- Resolution: A width of 1080px to 1920px delivers razor-sharp images on modern OLED screens.
- File size: Aim for the middle 500 KB and 2 MB. It provides maximum sharpness without the customer having to wait for the download if they are on a slower connection.
2. Video (MP4)
- Format & Codec: MP4 with H.264 video and AAC audio.
- Length & Size: Short, engaging clips of 5–15 seconds achieve the best conversion. Keep the file size under 10–15 MB if you want the video to play automatically in the preview.
- Application: Product presentations, short instructional videos, personal welcome greetings, or event trailers.
3. Document (PDF)
- Application: Invoices, tickets, booking confirmations, agreements and product catalogs.
- Best practice: Send the PDF file either as a direct attachment in the chat stream or embedded in a Rich Card with a clear Call-to-Action (CTA) like ”Download invoice” or ”View ticket”.
4. Contact Card (vCard / VCF)
- Application: Onboarding of new customers, customer service contact, or personal advisor.
- Best practice: When a vCard is sent via RCS, the messaging app recognizes the .vcf file type and displays a button to save the contact directly to the phonebook. This dramatically increases the response rate for future phone calls or SMS campaigns since your company name and logo are already saved on the customer's device.
RCS Rich Cards: The perfect framework for your content
Simply sending a file as a link rarely results in high conversion. It is in combination with RCS Rich Cards so the file transfer reaches its full potential.
A Rich Card makes it possible to combine a high-resolution image or video at the top, a headline, descriptive text, and interactive response buttons (Chip Buttons) at the bottom.
Three exciting use cases:
- E-commerce & Logistics Send a crisp product image directly in the chat with the delivery update, along with an embedded PDF return label.
- Finance & Insurance Deliver the month's invoice or insurance notice as a secure PDF via a verified corporate account, with a direct payment button.
- Travel & Events Send a high-resolution boarding pass or event ticket along with a vCard for the organizer's support number.
Why high-resolution media strengthens brand and conversion
When communication moves into the customer's primary chat app, the visual presentation becomes a direct reflection of your brand. A grainy MMS image signals outdated technology and can damage trust, while a razor-sharp RCS presentation provides a professional and reassuring impression.
By leveraging the RCS infrastructure with HTTP-based file transfer, you not only eliminate technical limitations – you create an interactive, visual, and converting customer experience directly on the mobile phone.