How to Estimate Image Server Storage Capacity
Image server capacity is easy to underestimate if you only count original files. In real operation, originals, thumbnails, temporary downloads, logs, and backup copies all grow together.
For example, 50,000 photos averaging 3 MB each require about 150 GB for originals alone. One backup copy turns that into 300 GB, and thumbnails plus temporary work files make it wise to keep at least 20% free space.
Calculation Order
Multiply photo count by average size to estimate originals. Then multiply by backup copies, add thumbnail cache and log growth separately, and leave room for filesystem overhead and recovery work.
Measuring Folder Size Yourself
For the average file size in your estimate, just measure one representative folder.
# du and df ship with Linux/macOS by default
# 1) total size of one representative folder (human-readable)
du -sh ~/uploads
# → "12G /home/me/uploads"
# 2) file count in that folder
find ~/uploads -type f | wc -l
# → 4820
# 3) average file size = 12GB ÷ 4820 ≈ 2.6MB
# put this average into the calculator above to estimate total storage
# 4) check free disk space
df -h /
# → shows usage like "Use% 63%". Expand before it passes 80%