diff --git a/assets/js/__tests__/upload.spec.ts b/assets/js/__tests__/upload.spec.ts
index 06d14d64..bd5d9c5e 100644
--- a/assets/js/__tests__/upload.spec.ts
+++ b/assets/js/__tests__/upload.spec.ts
@@ -25,6 +25,9 @@ const errorResponse = {
 };
 /* eslint-enable camelcase */
 
+const tagSets = ['', 'a tag', 'safe', 'one, two, three', 'safe, explicit', 'safe, explicit, three', 'safe, two, three'];
+const tagErrorCounts = [1, 2, 1, 1, 2, 1, 0];
+
 describe('Image upload form', () => {
   let mockPng: File;
   let mockWebm: File;
@@ -58,13 +61,23 @@ describe('Image upload form', () => {
   let scraperError: HTMLDivElement;
   let fetchButton: HTMLButtonElement;
   let tagsEl: HTMLTextAreaElement;
+  let taginputEl: HTMLDivElement;
   let sourceEl: HTMLInputElement;
   let descrEl: HTMLTextAreaElement;
+  let submitButton: HTMLButtonElement;
 
   const assertFetchButtonIsDisabled = () => {
     if (!fetchButton.hasAttribute('disabled')) throw new Error('fetchButton is not disabled');
   };
 
+  const assertSubmitButtonIsDisabled = () => {
+    if (!submitButton.hasAttribute('disabled')) throw new Error('submitButton is not disabled');
+  };
+
+  const assertSubmitButtonIsEnabled = () => {
+    if (submitButton.hasAttribute('disabled')) throw new Error('submitButton is disabled');
+  };
+
   beforeEach(() => {
     document.documentElement.insertAdjacentHTML(
       'beforeend',
@@ -77,7 +90,12 @@ describe('Image upload form', () => {
 
         <input id="image_sources_0_source" name="image[sources][0][source]" type="text" class="js-source-url" />
         <textarea id="image_tag_input" name="image[tag_input]" class="js-image-tags-input"></textarea>
+        <div class="js-taginput"></div>
+        <button id="tagsinput-save" type="button" class="button">Save</button>
         <textarea id="image_description" name="image[description]" class="js-image-descr-input"></textarea>
+        <div class="actions">
+          <button class="button input--separate-top" type="submit">Upload</button>
+        </div>
        </form>`,
     );
 
@@ -87,9 +105,11 @@ describe('Image upload form', () => {
     remoteUrl = assertNotUndefined($$<HTMLInputElement>('.js-scraper')[1]);
     scraperError = assertNotUndefined($$<HTMLInputElement>('.js-scraper')[2]);
     tagsEl = assertNotNull($<HTMLTextAreaElement>('.js-image-tags-input'));
+    taginputEl = assertNotNull($<HTMLDivElement>('.js-taginput'));
     sourceEl = assertNotNull($<HTMLInputElement>('.js-source-url'));
     descrEl = assertNotNull($<HTMLTextAreaElement>('.js-image-descr-input'));
     fetchButton = assertNotNull($<HTMLButtonElement>('#js-scraper-preview'));
+    submitButton = assertNotNull($<HTMLButtonElement>('.actions > .button'));
 
     setupImageUpload();
     fetchMock.resetMocks();
@@ -193,4 +213,42 @@ describe('Image upload form', () => {
       expect(scraperError.innerText).toEqual('Error 1 Error 2');
     });
   });
+
+  async function submitForm(frm): Promise<boolean> {
+    return new Promise(resolve => {
+      function onSubmit() {
+        frm.removeEventListener('submit', onSubmit);
+        resolve(true);
+      }
+
+      frm.addEventListener('submit', onSubmit);
+
+      if (!fireEvent.submit(frm)) {
+        frm.removeEventListener('submit', onSubmit);
+        resolve(false);
+      }
+    });
+  }
+
+  it('should prevent form submission if tag checks fail', async () => {
+    for (let i = 0; i < tagSets.length; i += 1) {
+      taginputEl.value = tagSets[i];
+
+      if (await submitForm(form)) {
+        // form submit succeeded
+        await waitFor(() => {
+          assertSubmitButtonIsDisabled();
+          const succeededUnloadEvent = new Event('beforeunload', { cancelable: true });
+          expect(fireEvent(window, succeededUnloadEvent)).toBe(true);
+        });
+      } else {
+        // form submit prevented
+        frm = form;
+        await waitFor(() => {
+          assertSubmitButtonIsEnabled();
+          expect(frm.querySelectorAll('.help-block')).toHaveLength(tagErrorCounts[i]);
+        });
+      }
+    }
+  });
 });
diff --git a/assets/js/upload.js b/assets/js/upload.js
index 16d33959..0f931037 100644
--- a/assets/js/upload.js
+++ b/assets/js/upload.js
@@ -2,6 +2,7 @@
  * Fetch and display preview images for various image upload forms.
  */
 
+import { assertNotNull } from './utils/assert';
 import { fetchJson, handleError } from './utils/requests';
 import { $, $$, clearEl, hideEl, makeEl, showEl } from './utils/dom';
 import { addTag } from './tagsinput';
@@ -171,9 +172,98 @@ function setupImageUpload() {
     window.removeEventListener('beforeunload', beforeUnload);
   }
 
+  function createTagError(message) {
+    const buttonAfter = $('#tagsinput-save');
+    const errorElement = makeEl('span', { className: 'help-block tag-error', innerText: message });
+
+    buttonAfter.insertAdjacentElement('beforebegin', errorElement);
+  }
+
+  function clearTagErrors() {
+    $$('.tag-error').forEach(el => el.remove());
+  }
+
+  const ratingsTags = ['safe', 'suggestive', 'questionable', 'explicit', 'semi-grimdark', 'grimdark', 'grotesque'];
+
+  // populate tag error helper bars as necessary
+  // return true if all checks pass
+  // return false if any check fails
+  function validateTags() {
+    const tagInput = $('textarea.js-taginput');
+
+    if (!tagInput) {
+      return true;
+    }
+
+    const tagsArr = tagInput.value.split(',').map(t => t.trim());
+
+    const errors = [];
+
+    let hasRating = false;
+    let hasSafe = false;
+    let hasOtherRating = false;
+
+    tagsArr.forEach(tag => {
+      if (ratingsTags.includes(tag)) {
+        hasRating = true;
+        if (tag === 'safe') {
+          hasSafe = true;
+        } else {
+          hasOtherRating = true;
+        }
+      }
+    });
+
+    if (!hasRating) {
+      errors.push('Tag input must contain at least one rating tag');
+    } else if (hasSafe && hasOtherRating) {
+      errors.push('Tag input may not contain any other rating if safe');
+    }
+
+    if (tagsArr.length < 3) {
+      errors.push('Tag input must contain at least 3 tags');
+    }
+
+    errors.forEach(msg => createTagError(msg));
+
+    return errors.length === 0; // true: valid if no errors
+  }
+
+  function disableUploadButton() {
+    const submitButton = $('.button.input--separate-top');
+    if (submitButton !== null) {
+      submitButton.disabled = true;
+      submitButton.innerText = 'Please wait...';
+    }
+
+    // delay is needed because Safari stops the submit if the button is immediately disabled
+    requestAnimationFrame(() => submitButton.setAttribute('disabled', 'disabled'));
+  }
+
+  function submitHandler(event) {
+    // Remove any existing tag error elements
+    clearTagErrors();
+
+    if (validateTags()) {
+      // Disable navigation check
+      unregisterBeforeUnload();
+
+      // Prevent duplicate attempts to submit the form
+      disableUploadButton();
+
+      // Let the form submission complete
+    } else {
+      // Scroll to view validation errors
+      assertNotNull($('.fancy-tag-upload')).scrollIntoView();
+
+      // Prevent the form from being submitted
+      event.preventDefault();
+    }
+  }
+
   fileField.addEventListener('change', registerBeforeUnload);
   fetchButton.addEventListener('click', registerBeforeUnload);
-  form.addEventListener('submit', unregisterBeforeUnload);
+  form.addEventListener('submit', submitHandler);
 }
 
 export { setupImageUpload };
diff --git a/lib/philomena_web/templates/image/new.html.slime b/lib/philomena_web/templates/image/new.html.slime
index dfb664d9..2a080eb1 100644
--- a/lib/philomena_web/templates/image/new.html.slime
+++ b/lib/philomena_web/templates/image/new.html.slime
@@ -88,4 +88,4 @@
   = render PhilomenaWeb.CaptchaView, "_captcha.html", name: "image", conn: @conn
 
   .actions
-    = submit "Upload", class: "button input--separate-top", autocomplete: "off", data: [disable_with: "Please wait..."]
+    = submit "Upload", class: "button input--separate-top", autocomplete: "off"