Cities: Skylines

Cities: Skylines

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Uploading Custom Asset Thumbnails (Explained)
By ThatEvan
   
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Importance of Custom Thumbnails
Introduction
These days the workshop is oversaturated with thousands of items that do not have proper preview images. Taking the time to add a custom preview images could be the difference between your item getting a great amount of attention or to little to none. Small efforts such as this will likely draw more attention to your item.

Comparission between a custom Preview Image and a default Preview Image

(which one would you choose?)
Importing Images (Editor)
Snapshot Tool

If you do not wish to make custom thumbnails for how your item displays in game (the asset icon itself and the tooltip image) you may use the snapshot tool before beginning the save process. The snapshot tool can be found in the toolbar (camera icon) as it allows you to take a "snapshot" of your asset instead of adding your own.

Adding the Snapshot Image

The Snapshot image will display in the content manager of the Cities Skylines homescreen. Subscribers will be able to see this image only within the content manager but also defaults as the Steam Preview Image (you can change that later). Click on the small folder icon to open up your file explorer. Drag your image into the folder to replace the file (snapshot.png). Make sure your .png file is named exactly as the original or else that game will not recognize the new file. Make sure your image is the same resolution as the one you just replaced. The file cannot exceed twelve megabytes. Smaller file sizes may help you upload prop packs with multiple items.


(snapshot and tooltip images)

Adding the Thumbnail Image

The Thumbnail is how your item will display in the game toolbar (ex: road icon). Your Thumbnail should be simple and easy to recognize.


(thumbnail and tooltip images)

Follow the same steps above to replace the Thumbnail (asset_thumb) as well as making sure to rename the file exactly. Your Thumbnail[/b] should be 109 x 100 pixels.
Repeat the same steps above for your Tooltip Image (asset_tooltip). This will be the preview of your asset that will appear while hovering over your asset in the toolbar

Make sure your Tooltip Image is 492 × 147 pixels to prevent stretching.


Compressing Your Own Images?
Cities: Skylines will compress asset files (.crp files) automatically once saved from the editor. If you feel the need to decrease your image filesizes, you can compress .png files online or through use of sofware (photoshop, gimp, etc.). However from my experience, this only saves around 100kb.


debug statement from console skipping image compression
Uploading Your Asset to the Workshop
First, Open your content manager from the home menu of Cities: Skylines. Click the assets tab located on the sidebar and then search for your asset. If your list is sorted differently find the dropdown box at the bottom of the window and select sort by name. Your item should display a SHARE icon. Click the SHARE icon in order to open up the Workshop Importer


(content manager window)

Click the folder icon to open the file explorer window. The PreviewImage image will be your Steam Workshop Thumbnail that will display on the Workshop. Replace the file with your own and rename it "PreviewImage.png"
(this image should be 512x512px)


(workshop upload window)

This image should be a 1:1 ratio

Any other ratios will result in black bars covering the top and bottom of the thumbnail

Once your are finished, click the publish button.
Workshop Page
Adding images to your Workshop page is important. More images are always good to have and I would recommend adding around 3 images. You can also add a YouTube video and a 3d model if you wish.

Use the menu on the right to add your..
  • Title and Description
  • Images
  • Links
  • Contributors


(workshop page)

Adding Reqired Items
If you added a prop to your asset while in the asset editor (that is not vanilla) you will need to add that required prop to the required items list. Users who are not already subscribed to that item will not have that item included in your final work.

Adding Required DLC
ex: you make a tram station and upload it to the workshop
your asset will only work for users with the Snowfall DLC


Questions? Comments? Feedback?
No question is a bad question, ask away!

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8 Comments
Vadicus 1 Mar, 2023 @ 8:24am 
I'm having a new issue with the Snapshot tool and auto generated Asset Thumbnails. The editor now makes a Black background on the asset_thumb.png. It used to be transparent. Now ingame, the icons all have huge black backgrounds instead of blending in with the toolbar backdrop color. This isn't a huge issue but it's a bit annoying having the make custom asset thumbs for all saves.
MB 20 Jul, 2019 @ 11:19am 
Thanks, I had read that manual but since it talked about thumbnail/tooltip images only before sharing the model I was unsure.
I just tried it out, loaded the subscribed model into the asset editor, modified and saved it with new images, same name. Then in the content manager - where both the new and old version would now be listed - I clicked "Update" for the new version and yes, it correctly updated the workshop item with the new thumbnail image. (No need to copy files around in the file system.)
Thanks again for the tip! :steamhappy:
ThatEvan  [author] 20 Jul, 2019 @ 10:00am 
@MB in order to replace the thumbnail image and/or the tooltip image, you will need to re-import the asset (preferably with the same name) and then update your item.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=424748932
MB 20 Jul, 2019 @ 6:53am 
Is it possible (and if so, how) to update the thumbnail and tooltip images once the asset is shared on the workshop. I can easily replace the preview image, but not the other two images.

Thanks for sharing your knowledge.
ThatEvan  [author] 31 Dec, 2018 @ 9:55pm 
guide updated with new photos and grammatical errors fixed :2018bestcoffee:
GustavFrings 30 Dec, 2018 @ 9:32am 
Perfect guide. Explains everything you need. Thanks!
AturUwU 27 Aug, 2018 @ 10:57am 
whats with having a custom thumbnail ingame?
Swesim 12 Jul, 2017 @ 8:13am 
Very useful guide, now I just have to find out how to add the required custom props as I only get finished assets in my list when I try to find the dependencies myself.