Raster cell size changing with new projection

[tt1]

I have a high-resolution World View 2 satellite image with a cell size of 0.5 m. However the image is in a WGS84 coordinate system, so to get meter distance values instead of degrees I have converted it to a WGS84 / UTM projection.

The raster in WGS84 / UTM projection has a cell size of 0.35.

How can I convert the image into a WGS84 / UTM projection and maintain the 0.5 m cell size?

I am using ArcGIS Pro and converted the coordinate system from WGS84 to WGS84 / UTM using "raster project" tool.

[MervynLotter]

You have used the wrong geoprocessing tool to project your raster. Define Projection is used to assign the correct projection to an existing raster or feature layer. You usually use this when you have received a file generated from some other software that did not include a .prj file, or raster equivalent. 

See Define Projection—Data Management toolbox | Documentation 

You must use the Project Raster geoprocessing tool to project a raster to a new projection. 

Project Raster—Data Management toolbox | Documentation 

[tt1]

Apologies, I did indeed use project raster. I confused the tool's name. Thanks for flagging. 

[MervynLotter]

Have you tried an equal area projection? Not sure if this will solve the issue but it may be related to your choice in projection. Where in the world is your study area?  

[DanPatterson]

Projecting rasters has many considerations, one of which is the coordinates system

Project Raster—Data Management toolbox | Documentation 

But... Do not skip a read on Pro's cell size projection method.  It is well worth the read.

How the Cell Size Projection Method environment setting works—Geoprocessing | Documentation 

Cell Size Projection Method (Environment setting)—Geoprocessing | Documentation