diff --git a/src/drawerbase.js b/src/drawerbase.js
index f2279b62..e2f32338 100644
--- a/src/drawerbase.js
+++ b/src/drawerbase.js
@@ -128,6 +128,16 @@ OpenSeadragon.DrawerBase = class DrawerBase{
         return undefined;
     }
 
+    /**
+     * Retrieve required data formats the data must be converted to.
+     * This list MUST BE A VALID SUBSET OF getSupportedDataFormats()
+     * @abstract
+     * @return {string[]}
+     */
+    getRequiredDataFormats() {
+        return this.getSupportedDataFormats();
+    }
+
     /**
      * Retrieve data types
      * @abstract
diff --git a/src/tilecache.js b/src/tilecache.js
index 87a1f0b7..e7f10b2b 100644
--- a/src/tilecache.js
+++ b/src/tilecache.js
@@ -256,22 +256,29 @@
             }
 
             internalCache = internalCache[drawerId];
-            if (internalCache) {
+            if (internalCache && supportedTypes.includes(internalCache.type)) {
                 // already done
                 return $.Promise.resolve(this);
             }
 
-            internalCache = this[DRAWER_INTERNAL_CACHE][drawerId] = new $.SimpleCacheRecord();
             const conversionPath = $.convertor.getConversionPath(this.type, supportedTypes);
             if (!conversionPath) {
                 $.console.error(`[getDataForRendering] Conversion ${this.type} ---> ${supportedTypes} cannot be done!`);
                 return $.Promise.resolve(this);
             }
-            internalCache.withTileReference(this._tRef);
+            const newInternalCache = new $.SimpleCacheRecord();
+
+            newInternalCache.withTileReference(this._tRef);
             const selectedFormat = conversionPath[conversionPath.length - 1].target.value;
             return $.convertor.convert(this._tRef, this.data, this.type, selectedFormat).then(data => {
-                internalCache.setDataAs(data, selectedFormat);  // synchronous, SimpleCacheRecord call
-                return internalCache;
+                newInternalCache.setDataAs(data, selectedFormat);  // synchronous, SimpleCacheRecord call
+
+                // if existed, delete
+                if (internalCache) {
+                    internalCache.destroy();
+                }
+                this[DRAWER_INTERNAL_CACHE][drawerId] = newInternalCache;
+                return newInternalCache;
             });
         }
 
diff --git a/src/webgldrawer.js b/src/webgldrawer.js
index 6d01b6fe..57094e37 100644
--- a/src/webgldrawer.js
+++ b/src/webgldrawer.js
@@ -100,9 +100,9 @@
             this._setupCanvases();
             this._setupRenderer();
 
-            this._supportedFormats = [];
+            this._supportedFormats = this._setupTextureHandlers();
+            this._requiredFormats = this._supportedFormats;
             this._setupCallCount = 1;
-            this._setupTextureHandlers();
 
             this.context = this._outputContext; // API required by tests
         }
@@ -468,6 +468,10 @@
 
         }
 
+        getRequiredDataFormats() {
+            return this._requiredFormats;
+        }
+
         // Public API required by all Drawer implementations
         /**
         * Sets whether image smoothing is enabled or disabled
@@ -476,7 +480,12 @@
         setImageSmoothingEnabled(enabled){
             if( this._imageSmoothingEnabled !== enabled ){
                 this._imageSmoothingEnabled = enabled;
-                this._setupTextureHandlers();  // re-sets the type to enforce re-initialization
+
+                // Todo consider removing old type handlers if _supportedFormats had already types defined,
+                // and remove support for rendering old types...
+                const newFormats = this._setupTextureHandlers();  // re-sets the type to enforce re-initialization
+                this._supportedFormats.push(...newFormats);
+                this._requiredFormats = newFormats;
                 return this.viewer.requestInvalidate();
             }
             return $.Promise.resolve();
@@ -892,8 +901,8 @@
                 // Set the parameters so we can render any size image.
                 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
                 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
-                gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
-                gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
+                gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, _this._textureFilter());
+                gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, _this._textureFilter());
 
                 try{
                     // This depends on gl.TEXTURE_2D being bound to the texture
@@ -919,8 +928,6 @@
             // Differentiate type also based on type used to upload data: we can support bidirectional conversion.
             const c2dTexType = thisType + ":context2d",
                 imageTexType = thisType + ":image";
-            // Todo consider removing old type handlers if _supportedFormats had already types defined
-            this._supportedFormats = [c2dTexType, imageTexType];
 
             // We should be OK uploading any of these types. The complexity is selected to be O(3n), should be
             // more than linear pass over pixels
@@ -929,6 +936,7 @@
 
             $.convertor.learnDestroy(c2dTexType, tex2DCompatibleDestructor);
             $.convertor.learnDestroy(imageTexType, tex2DCompatibleDestructor);
+            return [c2dTexType, imageTexType];
         }
 
         // private
diff --git a/src/world.js b/src/world.js
index 84eb1df8..a2836028 100644
--- a/src/world.js
+++ b/src/world.js
@@ -303,7 +303,7 @@ $.extend( $.World.prototype, $.EventSource.prototype, /** @lends OpenSeadragon.W
         // We call the event on the parent viewer window no matter what
         const eventTarget = this.viewer.viewer || this.viewer;
         // However, we must pick the correct drawer reference (navigator VS viewer)
-        const supportedFormats = this.viewer.drawer.getSupportedDataFormats();
+        const supportedFormats = this.viewer.drawer.getRequiredDataFormats();
         const keepInternalCacheCopy = this.viewer.drawer.options.usePrivateCache;
         const drawerId = this.viewer.drawer.getId();