# sitk.ComposeImageFilter with list of images (python)
**URL:** https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824
**Category:** Beginner Questions
**Tags:** python, simpleitk
**Created:** [April 3, 2018, 10:28pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824 "2018-04-03T22:28:09Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Diego\_C](https://discourse.itk.org/u/Diego_C)
#### Post date: [April 3, 2018, 10:28pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/1 "2018-04-03T22:28:09Z")
Hello!
I am trying to use the ComposeImageFilter to combine three grayscale volumes into an RGB volume. All my images have the same metadata in regards of origin, spacing, dimensions,etc…
This is what I am doing:
```auto
def compose_image(image_list):
filter = sitk.ComposeImageFilter(image_list)
return filter.Execute()
```
From the ITK documentation I get this is possible since the Execute method is overloaded and one of the versions receives a vector:
What am I doing wrong?
Thanks,
Diego
---
### Author:  [@blowekamp](https://discourse.itk.org/u/blowekamp)
#### Post date: [April 3, 2018, 11:15pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/2 "2018-04-03T23:15:02Z")
You are passing the arguments for the execute method to the constructor. Are you wanting to use the procedural or the object oriented interface?
---
### Author:  [@Diego\_C](https://discourse.itk.org/u/Diego_C)
#### Post date: [April 3, 2018, 11:24pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/3 "2018-04-03T23:24:08Z")
I saw that! sorry! I tried to delete this post but I don’t have that option.
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [April 4, 2018, 3:20pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/4 "2018-04-04T15:20:52Z")
I reverted your edit. @matt.mccormick and @fbudin can probably delete the post, but I see no reason for that. You should not be ashamed for asking questions!
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### Author:  [@Diego\_C](https://discourse.itk.org/u/Diego_C)
#### Post date: [April 6, 2018, 12:31am UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/5 "2018-04-06T00:31:29Z")
Hi Dženan! I am not worried about asking, it is just that it was silly because I passed the list of images to the constructor instead of passing it to the execute method (this is what happens when you code past midnight lol). I noticed and I tried to delete the question but it was too late… 🤦🏽♂️ and I had a DUH! moment.
---
### Author:  [@fbudin](https://discourse.itk.org/u/fbudin)
#### Post date: [April 6, 2018, 1:12pm UTC](https://discourse.itk.org/t/sitk-composeimagefilter-with-list-of-images-python/824/6 "2018-04-06T13:12:27Z")
Other people might make the same late night mistake. Having an explanation of what they should have done is helpful. Thanks for asking the question!