diff --git a/src/shared/localization.ts b/src/shared/localization.ts
index d2550cb5..6218087b 100644
--- a/src/shared/localization.ts
+++ b/src/shared/localization.ts
@@ -86,8 +86,11 @@ export const defaultStrings = {
             "Your image is too large to upload (over 2 MiB)" as string,
         upload_error_generic:
             "Image upload failed. Please try again." as string,
-        upload_error_unsupported_format:
-            "Please select an image (jpeg, png, gif) to upload" as string,
+        upload_error_unsupported_format: ({
+            supportedFormats,
+        }: {
+            supportedFormats: string;
+        }) => `Please select an image (${supportedFormats}) to upload`,
         uploaded_image_preview_alt: "uploaded image preview" as string,
     },
 } as const;
diff --git a/src/shared/prosemirror-plugins/image-upload.ts b/src/shared/prosemirror-plugins/image-upload.ts
index f1acd3be..71f90ab2 100644
--- a/src/shared/prosemirror-plugins/image-upload.ts
+++ b/src/shared/prosemirror-plugins/image-upload.ts
@@ -57,6 +57,12 @@ export interface ImageUploadOptions {
      * If true, allow users to add images via an external url
      */
     allowExternalUrls?: boolean;
+    /**
+     * An array of strings containing the accepted file types for the image uploader.
+     * See https://developer.mozilla.org/en-US/docs/Web/Media/Formats/Image_types for appropriate image
+     * file types.
+     */
+    acceptedFileTypes?: string[];
 }
 
 /**
@@ -84,6 +90,8 @@ export async function defaultImageUploadHandler(file: File): Promise<string> {
     return json.UploadedImage;
 }
 
+const defaultAcceptedFileTypes = ["image/jpeg", "image/png", "image/gif"];
+
 enum ValidationResult {
     Ok,
     FileTooLarge,
@@ -125,6 +133,7 @@ export class ImageUploader extends PluginInterfaceView<
         super(INTERFACE_KEY);
 
         const randomId = generateRandomId();
+        const acceptedFileTypes = uploadOptions.acceptedFileTypes || [];
         this.isVisible = false;
         this.uploadOptions = uploadOptions;
         this.validateLink = validateLink;
@@ -137,7 +146,7 @@ export class ImageUploader extends PluginInterfaceView<
         this.uploadField = document.createElement("input");
         this.uploadField.type = "file";
         this.uploadField.className = "js-image-uploader-input v-visible-sr";
-        this.uploadField.accept = "image/*";
+        this.uploadField.accept = acceptedFileTypes?.join(", ");
         this.uploadField.multiple = false;
         this.uploadField.id = "fileUpload" + randomId;
 
@@ -148,7 +157,7 @@ export class ImageUploader extends PluginInterfaceView<
             <div class="fs-body2 p12 pb0 js-cta-container">
                 <label for="${this.uploadField.id}" class="d-inline-flex f:outline-ring s-link js-browse-button" aria-controls="image-preview-${randomId}">
                     Browse
-                </label>, drag & drop<span class="js-external-url-trigger-container d-none">, <button type="button" class="s-btn s-btn__link js-external-url-trigger">enter a link</button></span>, or paste an image <span class="fc-light fs-caption">Max size 2 MiB</span>
+                </label>, drag & drop<span class="js-external-url-trigger-container d-none">, <button type="button" class="s-btn s-btn__link js-external-url-trigger">enter a link</button></span>, or paste an image.
             </div>
 
             <div class="js-external-url-input-container p12 d-none">
@@ -175,6 +184,21 @@ export class ImageUploader extends PluginInterfaceView<
             </div>
         `;
 
+        // add the caption element to the cta container
+        const ctaContainer =
+            this.uploadContainer.querySelector(".js-cta-container");
+        const acceptedFileTypesString = acceptedFileTypes?.length
+            ? acceptedFileTypes.join(", ").replace(/image\//g, "")
+            : "";
+
+        if (acceptedFileTypesString) {
+            const breakEl = document.createElement("br");
+            ctaContainer.appendChild(breakEl);
+        }
+        ctaContainer.appendChild(
+            this.getCaptionElement(acceptedFileTypesString)
+        );
+
         // add in the uploadField right after the first child element
         this.uploadContainer
             .querySelector(`.js-browse-button`)
@@ -286,6 +310,19 @@ export class ImageUploader extends PluginInterfaceView<
         event.stopPropagation();
     }
 
+    getCaptionElement(text: string): HTMLElement {
+        const uploadCaptionEl = document.createElement("span");
+        uploadCaptionEl.className = "fc-light fs-caption";
+
+        let captionText = "(Max size 2 MiB)";
+        if (text) {
+            captionText = `Supported file types: ${text} ${captionText}`;
+        }
+        uploadCaptionEl.innerText = captionText;
+
+        return uploadCaptionEl;
+    }
+
     handleFileSelection(view: EditorView): void {
         this.resetImagePreview();
         const files = this.uploadField.files;
@@ -311,7 +348,8 @@ export class ImageUploader extends PluginInterfaceView<
     }
 
     validateImage(image: File): ValidationResult {
-        const validTypes = ["image/jpeg", "image/png", "image/gif"];
+        const validTypes =
+            this.uploadOptions.acceptedFileTypes ?? defaultAcceptedFileTypes;
         const sizeLimit = 0x200000; // 2 MiB
 
         if (validTypes.indexOf(image.type) === -1) {
@@ -385,7 +423,14 @@ export class ImageUploader extends PluginInterfaceView<
                 return;
             case ValidationResult.InvalidFileType:
                 this.showValidationError(
-                    _t("image_upload.upload_error_unsupported_format")
+                    _t("image_upload.upload_error_unsupported_format", {
+                        supportedFormats: (
+                            this.uploadOptions.acceptedFileTypes ||
+                            defaultAcceptedFileTypes
+                        )
+                            .join(", ")
+                            .replace(/image\//g, ""),
+                    })
                 );
                 reject("invalid filetype");
                 return;
diff --git a/test/shared/prosemirror-plugins/image-upload.test.ts b/test/shared/prosemirror-plugins/image-upload.test.ts
index bfd2b635..ab2997f5 100644
--- a/test/shared/prosemirror-plugins/image-upload.test.ts
+++ b/test/shared/prosemirror-plugins/image-upload.test.ts
@@ -151,6 +151,47 @@ describe("image upload plugin", () => {
             expect(validationMessage.classList).not.toContain("d-none");
         });
 
+        it("should accept files that match those provided in the acceptedFileTypes option", async () => {
+            setupTestVariables({
+                acceptedFileTypes: ["image/bmp"],
+            });
+
+            showImageUploader(view.editorView);
+
+            await expect(
+                uploader.showImagePreview(
+                    mockFile("some bmp file", "image/bmp")
+                )
+            ).resolves.toBeUndefined();
+            expect(findPreviewElement(uploader).classList).not.toContain(
+                "d-none"
+            );
+            expect(findAddButton(uploader).disabled).toBe(false);
+            const validationMessage = findValidationMessage(uploader);
+            expect(validationMessage.classList).toContain("d-none");
+        });
+
+        it("should reject unaccepted files when acceptedFileTypes option is defined", async () => {
+            setupTestVariables({
+                acceptedFileTypes: ["image/bmp"],
+            });
+
+            showImageUploader(view.editorView);
+
+            await expect(
+                uploader.showImagePreview(
+                    mockFile("some gif file", "image/gif")
+                )
+            ).rejects.toBe("invalid filetype");
+            expect(findPreviewElement(uploader).classList).toContain("d-none");
+            expect(findAddButton(uploader).disabled).toBe(true);
+            const validationMessage = findValidationMessage(uploader);
+            expect(validationMessage.textContent).toBe(
+                "Please select an image (bmp) to upload"
+            );
+            expect(validationMessage.classList).not.toContain("d-none");
+        });
+
         it("should hide error when hiding uploader", async () => {
             showImageUploader(view.editorView);