How to Reduce PNG Export File Size in Affinity Photo 2

PNG files are great. They look sharp. They support transparency. They are perfect for web graphics, logos, and screenshots. But there is one small problem. PNG files can get big. Very big. If you export them the wrong way in Affinity Photo 2, they may slow down your website or eat up storage space.

TLDR: To reduce PNG export file size in Affinity Photo 2, resize your image, remove unused layers, lower bit depth, and fine-tune export settings. Use indexed colors when possible. Strip out unnecessary metadata. A few small tweaks can shrink your PNG without ruining quality.

Now let’s break it down in a fun and simple way.

Why PNG Files Get So Large

Table of Contents

PNG stands for Portable Network Graphics. It uses lossless compression. That means no quality is lost when saving. Sounds great, right? Yes. But it also means large file sizes.

PNG files grow big when:

The image has large dimensions
It uses 16-bit color
There are many transparent pixels
There is hidden or unused data
The image has too many colors

The good news? You can control all of this.

Step 1: Resize Your Image First

This is the easiest win.

If your image is 4000 pixels wide but your website only shows 1200 pixels, you are wasting space. Those extra pixels add weight.

To resize in Affinity Photo 2:

Go to Document
Select Resize Document
Enter your new width and height
Click Resample if needed

Keep proportions locked. This avoids distortion.

Pro tip: For websites, 72 or 144 DPI is usually fine. You don’t need 300 DPI unless you are printing.

Smaller dimensions = smaller file. Simple math.

Step 2: Flatten Layers Before Export

Layers are amazing while editing. But they are not needed in a final PNG.

Extra layers add complexity. Sometimes hidden layers stay inside the file structure.

Before exporting:

Remove unused layers
Delete hidden assets
Merge visible layers if editing is done

Go to Layer → Merge Visible if you are ready to finalize.

This step alone can shrink your file noticeably.

Step 3: Lower the Bit Depth

This step is powerful.

Affinity Photo 2 allows 8-bit and 16-bit images. A 16-bit PNG stores more color data. It looks beautiful. But it doubles size in many cases.

For web use? You rarely need 16-bit.

To change bit depth:

Go to Document
Select Convert Format / ICC Profile
Choose RGB 8-bit

Click OK.

You just cut down the data load.

Step 4: Use Indexed Color When Possible

This is the secret weapon.

Indexed PNG files use a limited color palette. Instead of millions of colors, they may use 256 or fewer.

This is perfect for:

Logos
Icons
UI graphics
Simple illustrations

To convert:

Go to Document
Choose Convert Format / ICC Profile
Select Indexed 8-bit
Adjust color count if needed

Fewer colors = lighter file.

But be careful. Photos may show color banding if you reduce too much.

Step 5: Adjust PNG Export Settings

Now comes the final step. Exporting.

Go to:

File → Export
Select PNG

Here you will see several options.

Area Selection

Choose “Selection Only” if you don’t need the whole canvas.

Resample Before Export

Double-check dimensions here again.

Compression

PNG compression is lossless. Increase compression level. It won’t hurt quality. It might take slightly longer to process.

Metadata

Uncheck unnecessary metadata. Things like:

Camera info
Location data
Edit history

This data is invisible but adds weight.

Image not found in postmeta

Click export. Compare sizes. You should see improvement.

Step 6: Remove Transparent Padding

Transparent pixels still count in file dimensions.

If your logo sits in the center of a large transparent canvas, you are wasting space.

Fix this by cropping:

Select the Crop Tool
Trim empty edges
Apply crop

A tight canvas makes a lighter file.

Step 7: Simplify Effects

Some layer effects can increase complexity.

Examples:

Heavy shadows
Large glows
Complex blur effects

If they are subtle, keep them. If they are extreme, consider simplifying.

Sometimes rasterizing effects can help stabilize output.

Step 8: Check for Hidden Alpha Complexity

PNG supports transparency. That is fantastic.

But soft transparency gradients require more data than solid transparency.

If possible:

Use solid transparent areas
Avoid unnecessary feathering
Simplify masked regions

This is especially important for icons.

Step 9: Compare Before and After

Do a simple test.

Export once with default settings
Export again using optimized steps
Compare file sizes

You may see:

5 to 20 percent reduction with basic changes
Up to 70 percent smaller using indexed color for logos

Test visually, too. Zoom in. Make sure quality still looks good.

When Not to Use PNG

Sometimes the best fix is using a different format.

Consider:

JPEG for photos without transparency
WebP for modern web projects
SVG for vector logos

PNG is powerful. But not always the lightest choice.

Quick Checklist Before You Export

Here is your fast reminder list:

Resize image dimensions
Convert to 8-bit RGB
Use indexed color for simple graphics
Remove extra layers
Crop empty space
Increase compression setting
Strip metadata

Run through this list each time. It takes less than a minute once you get used to it.

Real World Example

Let’s say you created a logo.

Original settings:

4000 x 4000 pixels
16-bit color
Full RGB
No compression adjustments

File size: 12 MB.

After optimization:

1200 x 1200 pixels
8-bit indexed color
Cropped canvas
High compression
No metadata

New file size: 600 KB.

That is a massive difference. And it still looks perfect on a website.

Final Thoughts

Reducing PNG file size in Affinity Photo 2 is not complicated. It just requires attention.

Think in layers. Think in pixels. Think in colors.

Most large PNG files happen because of:

Oversized dimensions
Too many colors
High bit depth
Unnecessary data

Fix those. Your files shrink.

Small files load faster. Faster sites rank better. Users stay longer. Everyone wins.

Now open Affinity Photo 2. Try these steps. Watch your PNG files go from heavy to lightweight in minutes.

Simple tweaks. Big results.