provide own buffer for images

[codecov[bot]]

Codecov Report

Merging #233 (6e15ace) into master (b623c8c) will increase coverage by 0.03%. The diff coverage is 92.30%.

@@            Coverage Diff             @@
##           master     #233      +/-   ##
==========================================
+ Coverage   73.48%   73.52%   +0.03%     
==========================================
  Files          32       32              
  Lines        6158     6171      +13     
==========================================
+ Hits         4525     4537      +12     
- Misses       1633     1634       +1     

Impacted Files	Coverage Δ
src/drawings.jl	63.63% <92.30%> (+1.70%)	:arrow_up:

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[cormullion]

Thanks!