# What does attachment\_fu do when saving?

**URL:** <https://www.ruby-forum.com/t/what-does-attachment-fu-do-when-saving/189052>\
**Category:** Rails\
**Created:** [May 23, 2010, 8:58am UTC](https://www.ruby-forum.com/t/what-does-attachment-fu-do-when-saving/189052 "2010-05-23T08:58:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ssk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/82dd89/32.png) [@ssk](https://www.ruby-forum.com/u/ssk)\
**Post date:** [May 23, 2010, 8:58am UTC](https://www.ruby-forum.com/t/what-does-attachment-fu-do-when-saving/189052/1 "2010-05-23T08:58:12Z")

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Hi,

I have a model with attachment\_fu.  
The model saves images but I didn’t put validates\_as\_attachment.

I understand that it takes long time to create an object as it has to  
process images.  
But I don’t understand why it takes long time to update the object (not  
changing file but only modify other non-attachment\_fu attributes).  
If I do object.save(false), it doesn’t take long time.

So my question is…  
What’s the difference between object.save and object.save(false) when  
the object is attachment\_fu model and there’s no validation?

Thanks.

Sam