Business Central 2026 Adds In-Browser Image Previews: File.ViewFromStream Guide

That sounds minor. In practice it removes one of the clumsier daily tasks in an ERP system: download a receipt photo, find it in the Downloads folder, open it, then go back to the browser tab you were working in.

What changes for users​

The roadmap entry describes a viewer for images that works much like Business Central's existing print preview and PDF preview. You open an image attachment and it appears in the web client. If you still want a local copy, you can download it from the viewer.

Microsoft says the feature covers all areas of Business Central, including agents, email, and code from extensions. Thumbnails also get two upgrades:

• Animated GIF thumbnails in FactBoxes: GIF files can be used as FactBox thumbnails, and they animate if they have up to 48 frames. That limit applies to thumbnails only. The roadmap does not say full previews are capped at 48 frames.
• Thumbnails you can click: Clicking a thumbnail of an image, or of the first page of a PDF, opens the previewer.

Summary: Users can now inspect supported images without leaving Business Central. Downloading a copy is still an option.

Supported file formats​

Here are the formats the roadmap entry lists:

Watch the Safari caveat. If your accounts payable team scans invoices to TIFF and uses Edge or Chrome, the roadmap does not promise in-browser preview for those files. The entry also leaves out browser version requirements, file size limits and image dimension limits, so test with your own typical files before you announce anything to staff.

How this grew out of PDF preview​

Image preview builds on a feature from 2025. In Business Central 2025 release wave 1 (version 26), Microsoft added in-client PDF preview. Microsoft's release plan for that wave said it requires an uptake from extension developers because two new AL methods have been added to capture this new behavior, following the pattern of the File.Download method, and that the feature was now used in various areas of Business Central, such as document attachments and incoming documents.

Image support was the obvious gap. Business Central MVP Yun Zhu wrote about the 2026 release wave 2 (BC29) preview, which became available in early September. He noted that the earlier native feature does not support image files, so developers who wanted image previews had to build them themselves. The public preview for Dynamics 365 Business Central 2026 release wave 2 (BC29) is available, he wrote, and the image preview description he quoted matches the roadmap entry.

For on-premises administrators, that history matters. Partners have spent about eighteen months writing custom image viewers and control add-ins. Some of that code can now be retired.

Summary: This is the second phase of the PDF previewer from 2025 wave 1, and it closes a gap that partners had been patching with custom code.

What extension developers need to do​

This is the part most likely to cause trouble. The phrase "works across all areas" comes with a condition: according to the roadmap, extension developers must add support using File.ViewFromStream for Business Central online or File.View for on-premises. In Yun Zhu's summary, extension developers must add support for this feature using File.ViewFromStream for Business Central online, or File.View for Business Central on-premises. These methods follow the pattern of the File.Download method.

What the methods look like today:

• Microsoft Learn says File.ViewFromStream is available or changed with runtime version 15.0 and opens a file from the server on the client computer in preview mode.
• The signature is File.ViewFromStream(InStream: InStream, FileName: Text [, AllowDownloadAndPrint: Boolean]). The optional Boolean controls whether users can download or print from the viewer.
• The AL changelog for the original release also defined the on-premises method as File.View(FilePath: String [, AllowDownloadAndPrint: Boolean]), so on-premises code passes a file path, not a stream.

One documentation gap. The Microsoft Learn reference page for File.ViewFromStream still says the method works only in Business Central online and supports PDF files. That page was last updated in April 2025, long before this roadmap entry. Read it as out of date, not as proof that images won't work, and check the reference again once the 2026 wave 2 documentation is updated.

A practical test checklist​

1. Find your download paths. Search your extensions for places where image attachments are passed to File.Download. Those are the obvious candidates for a View call.
2. Keep online and on-premises separate. Use ViewFromStream online and File.View on-premises. They are not interchangeable.
3. Handle the return value. Both methods return a Boolean. Stefano Demiliani noted when PDF preview launched that if the loaded file is not supported for previewing, an error message will be displayed. Decide whether your code should fall back to a download.
4. Check file naming. When PDF preview first shipped, Business Central Ex reported that a non-PDF file but the file name ends with .pdf would still be sent to the previewer and produce an error. The extension on the FileName you pass evidently matters, so test mislabeled images too. That observation is about the 2025 PDF behavior; image handling has not been independently confirmed.
5. Test in more than one browser. Include Safari if you rely on TIFF.
6. Retire custom viewers carefully. If you built your own image preview, compare it with the native viewer before you remove it.

Summary: For users the feature is close to automatic. For extensions it is opt-in, and every image-handling code path needs a deliberate update.

The fine print for administrators​

• "Launched" doesn't mean it's in every tenant today. Microsoft's roadmap says it gives estimated release information that may change. Confirm the feature in your own environment after the 2026 wave 2 update reaches it.
• Scope: The entry lists the web platform and the worldwide multi-tenant cloud. Sovereign or government clouds are not mentioned.
• Governance: Previewing doesn't save a file to the endpoint unless the user clicks download, and the AllowDownloadAndPrint parameter lets developers turn downloading off altogether. My own read is that fewer unmanaged copies in Downloads folders is a small win for data hygiene. Microsoft does not make that claim.

The verdict​

This won't top anyone's list of 2026 highlights, but it fixes a daily annoyance. In-client preview now covers both PDFs and images, with animated thumbnails and clickable PDF first pages. The weak spot is third-party code: users will only notice the improvement everywhere once their extension vendors switch from Download to View.

How many partner extensions will be updated by the end of the year? On the forums, we'd like to hear which ISVs have already shipped the change and which custom image viewers you're ready to remove.