diff --git a/test/tests/utilitiesTest.js b/test/tests/utilitiesTest.js
index 17ba91f..4033f7f 100644
--- a/test/tests/utilitiesTest.js
+++ b/test/tests/utilitiesTest.js
@@ -361,4 +361,179 @@ describe("Zotero.Utilities", function() {
 			assert.equal(newHTML, html);
 		});
 	});
+	
+	describe("getAutomaticAttachmentPreferences()", function () {
+		describe("Zotero.Prefs unavailable", function () {
+			it("should return defaults", function () {
+				let { enabledTypes, typeOrder } = Zotero.Utilities.getAutomaticAttachmentPreferences();
+				assert.deepEqual(Array.from(enabledTypes), ['pdf', 'epub', 'html']);
+				assert.deepEqual(typeOrder, ['pdf', 'epub', 'html']);
+			});
+		});
+
+		describe("Zotero.Prefs available", function () {
+			let automaticAttachmentTypes = new Set(['epub']);
+			let automaticAttachmentTypesOrder = ['html', 'epub', 'pdf'];
+			
+			before(function () {
+				Zotero.Prefs = {
+					get: function (pref) {
+						if (pref === 'automaticAttachmentTypes') {
+							return Array.from(automaticAttachmentTypes).join(',');
+						}
+						else if (pref === 'automaticAttachmentTypes.order') {
+							return automaticAttachmentTypesOrder.join(',');
+						}
+						return null;
+					}
+				};
+			});
+			
+			after(function () {
+				delete Zotero.Prefs;
+			});
+
+			it("should return pref values", function () {
+				let { enabledTypes, typeOrder } = Zotero.Utilities.getAutomaticAttachmentPreferences();
+				assert.deepEqual(Array.from(enabledTypes), ['epub']);
+				assert.deepEqual(typeOrder, ['html', 'epub', 'pdf']);
+			});
+		});
+	});
+
+	describe("shouldSaveAttachmentOfType()", function () {
+		let automaticAttachmentTypes = new Set(['epub']);
+		let automaticAttachmentTypesOrder = ['html', 'epub', 'pdf'];
+
+		before(function () {
+			Zotero.Prefs = {
+				get: function (pref) {
+					if (pref === 'automaticAttachmentTypes') {
+						return Array.from(automaticAttachmentTypes).join(',');
+					}
+					else if (pref === 'automaticAttachmentTypes.order') {
+						return automaticAttachmentTypesOrder.join(',');
+					}
+					return null;
+				}
+			};
+		});
+
+		after(function () {
+			delete Zotero.Prefs;
+		});
+
+		it("should use pref values", function () {
+			assert.isTrue(Zotero.Utilities.shouldSaveAttachmentOfType('epub'));
+			assert.isFalse(Zotero.Utilities.shouldSaveAttachmentOfType('pdf'));
+			assert.isFalse(Zotero.Utilities.shouldSaveAttachmentOfType('html'));
+		});
+		
+		it("should throw on an unknown type", function () {
+			assert.throws(() => Zotero.Utilities.shouldSaveAttachmentOfType('nonexistent--type'));
+		});
+	});
+
+	describe("filterAttachmentsToSave()", function () {
+		let automaticAttachmentTypes = new Set(['html', 'epub']);
+		let automaticAttachmentTypesOrder = ['html', 'epub', 'pdf'];
+
+		before(function () {
+			Zotero.Prefs = {
+				get: function (pref) {
+					if (pref === 'automaticAttachmentTypes') {
+						return Array.from(automaticAttachmentTypes).join(',');
+					}
+					else if (pref === 'automaticAttachmentTypes.order') {
+						return automaticAttachmentTypesOrder.join(',');
+					}
+					return null;
+				}
+			};
+		});
+
+		after(function () {
+			delete Zotero.Prefs;
+		});
+
+		it("should keep non-attachments", function () {
+			assert.deepEqual(
+				Zotero.Utilities.filterAttachmentsToSave([
+					{ itemType: 'book', title: 'Other stuff' },
+					{ itemType: 'attachment', mimeType: 'application/pdf' }
+				]),
+				[
+					{ itemType: 'book', title: 'Other stuff' }
+				]
+			);
+		});
+
+		it("should keep attachments of unknown types", function () {
+			assert.deepEqual(
+				Zotero.Utilities.filterAttachmentsToSave([
+					{ itemType: 'attachment', mimeType: 'application/pdf' },
+					{ mimeType: 'text/x-unknown' }
+				]),
+				[
+					{ mimeType: 'text/x-unknown' }
+				]
+			);
+		});
+
+		it("should keep only attachments of the first matching type", function () {
+			assert.deepEqual(
+				Zotero.Utilities.filterAttachmentsToSave([
+					{ mimeType: 'application/pdf' },
+					{ mimeType: 'text/html' },
+					{ mimeType: 'text/html' },
+					{ mimeType: 'application/epub+zip' },
+					{ mimeType: 'application/epub+zip' }
+				]),
+				[
+					{ mimeType: 'text/html' },
+					{ mimeType: 'text/html' }
+				]
+			);
+		});
+
+		it("should recognize multiple HTML MIME types and keep unknown type", function () {
+			assert.deepEqual(
+				Zotero.Utilities.filterAttachmentsToSave([
+					{ mimeType: 'text/html' },
+					{ mimeType: 'text/html' },
+					{ mimeType: 'application/xhtml+xml' },
+					{ mimeType: 'application/epub+zip' },
+					{ mimeType: 'application/octet-stream' }
+				]),
+				[
+					{ mimeType: 'text/html' },
+					{ mimeType: 'text/html' },
+					{ mimeType: 'application/xhtml+xml' },
+					{ mimeType: 'application/octet-stream' }
+				]
+			);
+		});
+
+		it("should recognize attachment with 'document' property as HTML", function () {
+			assert.deepEqual(
+				Zotero.Utilities.filterAttachmentsToSave([
+					{ mimeType: 'text/html' },
+					{ document: {} },
+					{ mimeType: 'application/epub+zip' }
+				]),
+				[
+					{ mimeType: 'text/html' },
+					{ document: {} }
+				]
+			);
+		});
+		
+		it("should return the exact same objects", function () {
+			let obj = { mimeType: 'text/html' };
+			assert.equal(
+				Zotero.Utilities.filterAttachmentsToSave([obj])[0],
+				obj
+			);
+		});
+	});
 });
diff --git a/utilities.js b/utilities.js
index 6808118..cd98cf9 100644
--- a/utilities.js
+++ b/utilities.js
@@ -1830,6 +1830,81 @@ var Utilities = {
 		}
 		return root.innerHTML;
 	},
+	
+	getAutomaticAttachmentPreferences() {
+		let enabledTypes = Zotero.Prefs && Zotero.Prefs.get('automaticAttachmentTypes').split(',');
+		let typeOrder = Zotero.Prefs && Zotero.Prefs.get('automaticAttachmentTypes.order').split(',');
+
+		// If either pref isn't available (not just empty), use defaults
+		enabledTypes = new Set(enabledTypes || ['pdf', 'epub', 'html']);
+		typeOrder = typeOrder || ['pdf', 'epub', 'html'];
+		
+		return { enabledTypes, typeOrder };
+	},
+
+	shouldSaveAttachmentOfType(type) {
+		if (!['pdf', 'epub', 'html'].includes(type)) {
+			throw new Error('Unknown type: ' + type);
+		}
+		
+		let { enabledTypes } = this.getAutomaticAttachmentPreferences();
+		return enabledTypes.has(type);
+	},
+	
+	/**
+	 * Given an array of items in translator JSON format, return the items that
+	 * should be saved according to the user's preferences. Non-attachment items
+	 * are always returned.
+	 *
+	 * @typedef {{ mimeType: string, url?: string, document?: Document, itemType?: string }} TranslatorItem
+	 * @param {TranslatorItem[]} itemsJSON
+	 * @returns {TranslatorItem[]}
+	 */
+	filterAttachmentsToSave(itemsJSON) {
+		let { enabledTypes, typeOrder } = this.getAutomaticAttachmentPreferences();
+		
+		let attachmentTypes = itemsJSON.map((attachment) => {
+			if (typeof attachment.itemType === 'string' && attachment.itemType !== 'attachment') {
+				return null;
+			}
+			if (attachment.mimeType === 'application/pdf') {
+				return 'pdf';
+			}
+			if (attachment.mimeType === 'application/epub+zip') {
+				return 'epub';
+			}
+			if (attachment.document
+				|| (Zotero.MIME
+					? Zotero.MIME.isWebPageType(attachment.mimeType)
+					: ['text/html', 'application/xhtml+xml'].includes(attachment.mimeType))
+			) {
+				return 'html';
+			}
+			return null;
+		});
+
+		// We want to keep everything that isn't an identifiable file attachment
+		let isNotKnownTypeFileAttachment = (attachment, i) => {
+			return attachmentTypes[i] === null
+				|| attachmentTypes[i] === 'html' && attachment.snapshot === false;
+		};
+		
+		for (let type of typeOrder) {
+			if (!enabledTypes.has(type)) {
+				continue;
+			}
+			if (attachmentTypes.includes(type)) {
+				return itemsJSON.filter((attachment, i) => {
+					if (isNotKnownTypeFileAttachment(attachment, i)) {
+						return true;
+					}
+					return attachmentTypes[i] === type || attachmentTypes[i] === null;
+				});
+			}
+		}
+		
+		return itemsJSON.filter(isNotKnownTypeFileAttachment);
+	},
 
 	// /**
 	//  * Provides unicode support and other additional features for regular expressions