---
title: "Customizing iOS PDF viewer icons | Nutrient SDK"
canonical_url: "https://www.nutrient.io/guides/ios/customizing-the-interface/changing-an-image-used-in-pspdfkit/"
md_url: "https://www.nutrient.io/guides/ios/customizing-the-interface/changing-an-image-used-in-pspdfkit.md"
last_updated: "2026-05-26T12:37:25.503Z"
description: "You can replace image resources used by Nutrient by registering a custom handler on the iOS SDK object as its imageLoadingHandler."
---

# Customizing iOS PDF viewer icons

You can replace image resources used by Nutrient by registering a custom handler on the [`SDK`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pspdfkit/sdk/application) object as its [`imageLoadingHandler`](https://www.nutrient.io/api/ios/documentation/pspdfkit/sdk/imageloadinghandler). This handler is a closure that gives you the image name and allows you to return a custom image. If you return `nil`, the default Nutrient image will be used. It’s best to set this closure in the app delegate or before any `UIViewController` is on the screen. Images are cached, so a change made after caching won’t do anything:

```swift

SDK.shared.imageLoadingHandler = { imageName in
    if imageName == "knob" {
        return UIGraphicsImageRenderer(size: CGSize(width: 20, height: 20)).image { context in
            UIBezierPath(rect: context.format.bounds).fill()
        }
    } else if imageName == "document" {
        return UIImage(named: "customDocumentImage")
    }
    return nil
}

```

## Asset Catalog

Nutrient uses vector images in asset catalogs. These images can be found in `PSPDFKit.framework/Assets.car` (which is located in `PSPDFKit.xcframework`) and `PSPDFKitUI.framework/Assets.car` (which is located in `PSDPDFKitUI.xcframework`). You can use a tool like [Asset Catalog Tinkerer](https://github.com/insidegui/AssetCatalogTinkerer) to browse the asset catalog.
---

## Related pages

- [Customize view control modals on iOS](/guides/ios/faq/modally-presented-view-controllers.md)
- [Customizing toolbar button styling on iOS](/guides/ios/customizing-the-interface/changing-the-design-of-the-default-buttons.md)