How to use Smart Objects

Use a Smart Object in seven steps

1. 1

   Open the photo

   Go to lilcactus.app and choose File› then Open… (Ctrl+O or ⌘O), or drag the photo onto the window. To follow along exactly, open the sample photo from this page.

2. 2

   Convert it to a Smart Object

   With the Background layer selected, choose Layer› then Smart Objects› then Convert to Smart Object. The picture doesn’t change, but the Properties panel now says Smart object.

   

   

3. 3

   Shrink it to 25%

   Choose Edit› then Free Transform (Ctrl+Alt+Shift+T or ⌥⇧⌘T). On the options bar (the strip under the menus), type 25 into W and press Tab: H changes to 25 too, because the link button beside them keeps the two in proportion. Then click the ✓ (Commit transform) at the right end of the options bar. The photo becomes a small picture in the middle of the canvas.

   

   

   

4. 4

   Give it more color: a Smart Filter

   Choose Image› then Adjustments› then Vibrance…, type 50 for Vibrance and click Apply. On a Smart Object the adjustment doesn’t change the stored picture: it becomes a Smart Filter, listed by the Smart Filters (1)… button at the bottom of the Layers panel.

   

   

5. 5

   Enlarge it back to full size

   Choose Edit› then Free Transform again, type 400 into W (four times the current size), press Tab and click ✓. Choose View› then Zoom In a few times and look at the jetty: the boards are as sharp as before you shrank them, because the Smart Object redraws from its stored original. The comparison at the top of this page shows a plain layer after the same three steps.

6. 6

   Change or remove the filter later

   Click Smart Filters (1)… The dialog lists the layer’s Smart Filters. Untick Vibrance: the dialog’s Stack result preview shows the photo without it. Tick it again and click Apply stack; Cancel or closing the dialog discards any changes.

   In the same dialog you can change a filter’s values or Opacity below the list, remove it with ×, or pick another filter, such as Gaussian Blur, in the menu and click Add.

   

   

7. 7

   Swap the picture with Replace Contents

   Choose Layer› then Smart Objects› then Replace Contents… and pick another image; to follow along, download the coffee photo (1536 × 1024 px, the same size as the lake photo). The new picture takes the old one’s place with the same transform and the Vibrance filter still on it. A replacement with the same pixel size lands at exactly the same size. This is how mockups work: place the Smart Object where the design should go once, then replace its contents for each version.

   

   

Edit what’s inside

Layer› then Smart Objects› then Edit Contents opens the stored picture in its own tab, named after the layer with “· Contents”. Edit it like any document: paint, add layers, crop. Then choose File› then Save Contents to Parent or press Ctrl+S or ⌘S: while that tab is open, the File menu’s Save item has this name. The Smart Object in the first document updates. Layer› then Smart Objects› then Export Contents… downloads the stored picture as a PSD, or as a Lil Cactus project if it holds things a PSD can’t.

When to use a Smart Object, and when not

• Use one for a picture you will resize more than once, place in a layout, filter and want to retune, or replace later.
• Don’t for a layer you will paint or retouch directly: the Brush, Eraser and healing tools can’t work on a Smart Object. Edit its contents, or turn it back into pixels with Layer› then Rasterize› then Rasterize Layer: the Rasterize Layer Appearance dialog lists what will be lost, the stored original and the Smart Filters, and Convert to Pixels keeps how the layer looks.

Fix common problems

The Smart Object looks soft after enlarging

It can’t be sharper than the picture stored inside. Enlarging past 100% of the original stretches its pixels, as with any photo.

The replaced picture came in larger or smaller

Replace Contents keeps the transform, so a picture with a different pixel size is scaled by the same amount as the old one. Choose Edit› then Free Transform and type a new W to fit it.

Save with the Smart Object kept

Until you save a project or PSD, File› then Save writes a flat picture back into the JPEG you opened, without the Smart Object; the first Save of a JPEG, including the sample, opens the Save Image dialog.

File› then Save As› then Lil Cactus Project… (Ctrl+Shift+S or ⇧⌘S) keeps the Smart Object, its stored picture and its Smart Filters. File› then Save As› then Photoshop (.psd)… keeps Smart Objects too, but Lil Cactus can keep only Gaussian Blur and Invert Smart Filters editable in a PSD, and only without a filter mask: a Smart Object with any other Smart Filter, such as this Vibrance, is saved as plain pixels. Lil Cactus lists those layers and asks before it saves, and it asks again at every later save of that PSD. After either Save As, File› then Save updates that file; for this page’s document, a Lil Cactus project is the format that keeps everything. File› then Export› then JPEG… (or another format) always writes a new, flat image. See how to open and save PSD files.

Coming from another editor

Photoshop

Layer › Smart Objects › Convert to Smart Object, Edit Contents and Replace Contents…

GIMP

Most filters in GIMP 3 stay editable as layer effects unless you tick Merge Filter in the filter’s dialog.

Smart Objects: questions and answers