ImageAssemble on a List of Images with an Incompatible Number of Channels

Questions
,
1

I have some images with an incompatible number of channels that I want to combine into a single image. Can I preprocess them so that I can use ImageAssemble? Thanks.

In[17]:= Head /@ {i1, i2, i3}
Out[17]= {Image, Image, Image}
In[18]:= ImageDimensions /@ {i1, i2, i3}
Out[18]= {{50, 200}, {300, 200}, {50, 200}}

Evaluating the following gives the message: ImageAssemble::chan:
Expecting images with a compatible number of channels.

In[19]:= ImageAssemble[{i1, i2, i3}];
In[20]:= ImageChannels /@ {i1, i2, i3}
Out[20]= {4, 3, 4}
2

It seems images one and three have an alpha channel (transparency value). You can take care of it with RemoveAlphaChannel[].

3

Or SetAlphaChannel on the one that’s missing a transparency.