# How to send images and media in Oysterun Send one or several media items once from a Session chat, then check order, the shared caption, and the difference between original and bounded display bytes. Use this guide to send one image or a group of images, video, audio, and files from an Oysterun Session. You will check the staged order, add one caption, send once, inspect the result, and understand when Oysterun stores a bounded display image instead of the full-size original. The short rule: one selection can contain one or several files. A multi-file Send should become one grouped user message with the attachments in order and one shared caption. A large supported static image may be replaced by a smaller display upload, so the image viewer's Download action does not always return the full-size original you selected. ## Before you start - Your Oysterun Host is connected and the target Session chat is open. - The message composer shows the **Attach files** control and the **Send message** action. - The files are available on your current device, and you are allowed to share every item with the Session's provider. - You have retained your own full-resolution original when it matters. Oysterun is not an original-image archive. **Starting screen:** open the relevant Session chat and scroll to the composer at the bottom. ## 1. Choose the media path that matches your goal File you choose What Oysterun may upload What to expect after Send Large static JPEG, PNG, or WebP A smaller display version when Oysterun can create one safely and it is smaller than the original The same visual subject and aspect ratio, with no second full-size original stored for that message A supported static image already within the display bound The original file bytes; Oysterun does not upscale it The image displays at its available dimensions Animated GIF, animated WebP or PNG, HEIC/HEIF, or an image Oysterun cannot safely convert The original file when the Session's upload limit allows it The file can send, but a browser preview is not guaranteed for every format Video, audio, or another non-image attachment The original attachment under the normal upload limit A playback control or downloadable file, depending on the format No visible compression switch is required. Oysterun decides whether a safe display image can be made during Send. Keep your local original when full resolution matters. ## 2. Send one image or media item 1. Choose **Attach files**. 1. In your device's file picker, choose one file and return to Oysterun. 1. In the **Files** panel, confirm that the filename and local preview or file information match your selection. The **Staged** badge means the file has not been uploaded yet. 1. If you chose the wrong file, use its **Cancel Upload** control or choose **Remove**, then select the correct file. 1. Type an optional caption in the **Send a message...** composer. 1. Choose **Send message** once. Checkpoint: one user message appears in the same Session with the chosen item. If you entered a caption, it appears once with that item. A single-file send uses the normal image, video, audio, or file presentation; it does not need to look like a multi-file group. ## 3. Send several items as one grouped message ![The complete Oysterun Session composer and Files panel showing two sample files in staged order with one shared caption.](../assets/publication/staged-ordered-group.jpg) Visible checkpoint: The Files panel shows 01-publication-note.txt before 02-oysterun-guide.png, both Staged, with one shared caption ready to send. ![One sent Oysterun timeline message containing the ordered file and image attachments with one shared caption.](../assets/publication/sent-ordered-group.jpg) Visible checkpoint: One sent message keeps the staged attachment order and displays the shared caption exactly once. 1. Choose **Attach files** and select all intended files in one picker, or return to **Attach files** until every item is in the same draft. 1. Open the **Files** panel and read the cards from first to last. This is the order the sent group should keep. 1. If the set or order is wrong, use **Cancel Upload** for an item or **Remove All**, then select the files again in the intended order before sending. 1. Type one optional caption in the composer. It is shared by the whole group. 1. Choose **Send message** once. While the send is running, Oysterun may show **Uploading N staged files for Send...**. About the Staged tooltip: a current tooltip may say the files will send as “one media event per file.” Do not use that tooltip as the final checkpoint. The supported result after Send is one grouped user message. If the timeline actually remains split after one reload, follow the recovery section instead of resending. Checkpoint: the timeline shows one grouped user message, every attachment remains in the staged order, and the shared caption appears once—not once per item. ## 4. Inspect the sent items ![A sample oyster illustration opened at its correct proportions in the complete Oysterun image viewer.](../assets/publication/safe-image-viewer.jpg) Visible checkpoint: The complete viewer preserves the sample image's subject and proportions and shows Zoom Out, 100%, Zoom In, and Download. 1. Find the message you just sent in the Session timeline. 1. For an image, choose **View** if Oysterun has not loaded it yet. Then select the displayed image to open the image viewer. 1. Use the visible viewer controls as needed: - Zoom Out - Percentage - Zoom In - Download 1. Confirm that the image keeps the subject and proportions of the selected file. The viewer may be showing the bounded upload rather than the full-size original. 1. For video or audio, use its playback control. For a downloadable attachment, use the download-arrow control beside its filename. 1. For a group, check every item from first to last, then confirm that the caption appears only once below the group. Checkpoint: every selected item is reachable in the sent message, its order is correct, and the caption is neither missing nor repeated. ## 5. Understand display size and downloaded bytes For a supported static JPEG, PNG, or WebP larger than the display bound, Oysterun can make the long edge no more than 1280 pixels, preserve the aspect ratio, and avoid upscaling. Lossy JPEG or WebP output uses a normal display-quality target near 0.75. If the result would not be smaller or the conversion is unsafe, Oysterun keeps the original upload instead. What Download means: Download retrieves the bytes stored for the message. For a bounded display image, those are the display-version bytes—not a hidden second copy of the full-size original. When conversion was skipped, the stored bytes are the original upload. Each image in a multi-file group is handled independently. One item can use a bounded display version while another keeps its original bytes; the group order and one-caption behavior do not change. ## 6. Recover safely when upload or display fails - **File uploads unavailable:** wait for the Session and media configuration to finish loading, then reopen the same Session once. If the control stays unavailable, stop and ask the Host manager to check file-upload availability. - **The file exceeds the limit:** use **Cancel Upload**, **Remove**, or **Remove All**, then choose a smaller permitted file. Do not keep pressing Send with the same over-limit draft. - **Media send failed:** reload the same chat once and inspect the timeline before retrying. If the message already exists, do not resend it. If it is absent and the draft remains, retry once after the connection settles. - **Failed to load image:** choose **Retry** once. If it still fails, use the available download control or stop; repeated sends do not repair the stored media. - **The group is split, reordered, or repeats the caption:** reload once and inspect the same sent message. If the problem remains, preserve the visible result and stop instead of sending the files again. Safe stop point: after one reload and one bounded retry, preserve the staged or sent message and the visible error. Do not create a duplicate media message merely to change its display. ## 7. Finish the check 1. Close the image viewer with its left-arrow control or return to the Session timeline. 1. Confirm that the message is still one item in the timeline, even when it contains several attachments. 1. Confirm the attachment order, the single caption, and whether the stored image may be a bounded display version. Finished: you sent the intended media once, inspected every visible item, and kept the distinction between your local original and the bytes Oysterun stored for display.